Table of contents: CSI iQLANDIA
- CSI iQLANDIA - case introduction
- Face recognition
- Marker (imprint)
- Dactyloscopy, station no. 1
- Trichology, station no. 2
- DNA fingerprinting, station no. 3
- Trace evidence, station no. 4
- Identikit, station no. 5
- Odor traces
- Live identikit
- Password strength
- Case conclusion
CSI iQLANDIA - case introduction
Today the Police entrusted CSI iQLANDIA with a serious case, that of the murder of the renowned scientist Dr Rush. She was found by her eighty-year-old neighbor, Mrs Carrot, early yesterday morning, as she went to return Dr Rush’s special rose shears. The scientist’s body was found on the sidewalk in her own garden right next to a renovated fountain. The murderer had clearly been in a hurry. The coroner determined the time of death as 7 o ‘clock the previous day, that is just after the Sprouting of Science event had finished, which involved planting flowers in the garden by her house.
Who was Dr Rush?
35-year-old Dr Rush was extremely hard-working – she traveled a lot, working not only in the Czech Republic, but also at the Cranfield Institute in Great Britain, where she conducted research on water as well as working independently on a secret project. In her free time she tried to get in plenty of relaxation and sport.
Become a member of the CSI iQLANDIA team and help catch the culprit! Your task is to eliminate the five of the six suspects who did not commit the murder, and reveal the murderer! To do so, use forensic disciplines at the prepared stations.
How to do it?
- Scan the QR code with the web application
- Go through all 5 numbered checkpoints one by one
- At each station, complete a task and eliminate one of the suspects in the app
Joe “The Elbow” Murray
Englishman Joe Murray, a former top tennis player and multiple Wimbledon winner, came to the Czech Republic in the 1990s. The high financial rewards from his tennis Grand Slams allowed him to live the high life. He had a particular weakness for fast cars, and had several in his garage, from Porsche to Ferrari. However, his bohemian lifestyle and some bad real estate investments cost Murray practically all his property.
Joe was forced to sell everything He invested his last money in a tennis school in Liberec, but it did not bring in as much money as he had expected. To make ends meet he spent so long training people on the court that he developed a growth on his elbow, which is why they called him Joe “The Elbow” Murray.
Although he was a handsome man for his age and in excellent physical condition, those around him often teased him for his strong English accent and wearing his socks pulled up high, always matching his sweatband and headband.
Joe “The Elbow” Murray was Dr Rush’s personal trainer for the last five years.
Height: 180 cm
Weight: 75 kg
Age: 45 years old
During her work at the scientific institute, Dr Rush became acquainted with Peter Stoker, successful entrepreneur, power plant director and patron of the institute. They shared a love of science and traveling, while Rush’s intelligence and passion made a big impression on Stoker. They went out together for two years before they got married. They only one who did not wish them well was Stoker’s then ten-year-old daughter, Caroline Sweet. She blamed her stepmother for stealing her father until her death.
Stoker and Rush made a lot of money.. Although outwardly their marriage seemed solid, the opposite was true. Due to their work commitments, they no longer had time for each other, quarreled frequently and for the last year Rush suspected her husband was being unfaithful to her with his assistant. She therefore filed for a divorce, which was very tempestuous, because it kicked off a vicious battle over property.
Height: 185 cm
Weight: 95 kg
Dr Clara Dotty rented premises in Dr Rush’s house for seven years. Here she ran the renowned “Super Smile” dental practice, intended primarily for VIP clients.
Even though the doctor always tried to look her best, Mother Nature unfortunately had not endowed her with much physical beauty. Her ghastly smile, protruding brown warts on her nose and fat hairy legs stuffed into red pumps were guaranteed to put off any potential suitor. She therefore dedicated her life to breeding cats. She loved her tomcat Tubbs so much she started taking him to her office, which Dr Rush was understandably not at all keen on, given that she was allergic to cat hair.
A week before her death, Dr Rush called the dentist into her office and threatened that unless she stopped taking her cat into work she would be forced to terminate the lease.
Obviously this was a shock for Clara, who did not want to lose such a lucrative location.
Height: 175 cm
Weight: 112 kg
Age: 48 years old
Dr Rush had loved flowers and flowering shrubs, in particular rhododendrons, since her childhood. She therefore had an enormous garden with an English lawn designed and created next to her house. Although she loved gardening and found it fulfilling, she did not have time for daily maintenance because of her work, and so she entrusted all care of her flora to the hands of an expert – Miranda Thorn. The flame-haired gardener with the appearance of a ‘60s flower child gladly accepted the opportunity to work for the renowned scientist. She visited Dr Rush three times a week, and sometimes as many as five times a week during heatwaves. Both ladies were united by a passion for gardening, and so they became inseparable friends. Ms Thorn first heard the tragic news of Dr Rush’s death while she was in the Netherlands, choosing a special variety of tulip for the scientist’s garden.
Age: 33 years old
Height: 175 cm
Weight: 70 kg
Caroline Sweet– an attractive, slender blonde with heavy eye make-up and in a pink apron – ran a small café and pastry shop next door to Murray’s tennis school. She made wonderful cakes and desserts and mixed the best soft ice cream for the children. Caroline was Doctor Rush’s stepdaughter.
Although outwardly she was very nice to everyone, she was bitter on the inside. She especially hated her (now former) stepmother – Dr Rush. She blamed her for wrecking her family when she was ten years old by stealing away her father Peter Stoker, who she left shortly before her death anyway.
Height: 155 cm
Weight: 45 kg
Age:23 years old
Stephen Little worked at the same scientific institute as Dr Rush. The combination of his name, height and table manners so wild a St Bernard could have filled itself up on what he spilled beneath him led his colleagues to nickname him Breadcrumb.
Little was secretly in love with Dr Rush all along. He brought her flowers from Ms Thorn the gardener every day and became the doctor’s scientific assistant in order to be as close to his beloved as possible. Because he himself was not overly hard-working, the position of assistant suited him down to the ground. As soon as he found out that Dr Rush did not reciprocate his feelings, and was furthermore working on a new project which she had hidden from him, he was furious. In his rage he gave his notice and left the scientific institute without any further explanation immediately.
Age: 35 years old
Height: 225 cm
Weight: 100 kg
- Forensic sciences are scientific methods of collecting and examining information about the past. Information thus acquired is used in judicial proceedings.
- Forensic is a Latin word, meaning “belonging to the forum,” the forum in question being the Forum Romanum, a large square in Rome where trials took place in ancient times.
- Here, for example, a doctor named Antistius presented his findings from examining the corpse of Julius Caesar, which later led to the apprehension of the culprits.
Face recognition is performed based on the geometric features of the face and comparing them to a database. Gender can also be determined, and people’s ages can be estimated. For example, it is used by cameras for face recognition, checking people at the airport, locating people on the battlefield or simply unlocking mobile phones. Facial recognition is classified as a biometric method.
Face recognition requires a preparatory stage which is the detection of the face in the scene. Detectors observe with a conventional camera and evaluate the positions of eyes and mouth. However, we do not have enough data in 2D (in-plane) because we lose information about the curvature of the face and the system is not hard to fool. More sophisticated 2D systems also use facial expressions to recognize a person, so, for example, to unlock the phone you might have to smile or frown.
More complex 3D facial recognition in space requires specialized equipment. A 3D camera takes the spatial data of a face and creates a depth map - a cluster of points that represents a face in space. 3D face recognition is primarily based on comparing two clusters of points in space (3D models) that contain a large number of important features.
[Hand] Step in front of the TV with a camera and see what information the software can find out about you.
Marker (from the French marquant – “showing [something]; leaving a mark, trace, impression, etc.”).
In criminology, distinguishing features, characteristic marks, specific signs and peculiarities which are important in identification due to their accidental occurrence, are known as markers. They are of high value during identification. Examples are characteristic formations on papillary lines (so-called dactyloscopic markers). Other examples of markers in forensic science are, for example, the barrel marks on a bullet, the firing pin of a pistol on a cartridge case, crowbar marks on a door frame, a scratched lock, a footprint in the dirt, etc...
[Hand] Create a unique marker of your body by squeezing yourself between the bars. This marker is not permanent, so don't forget to take a picture!
Dactyloscopy, station no. 1
Mini-story: The video recording shows that the perpetrator was disturbed by a loud alarm, and so decided to flee. A partial fingerprint was found on the button which triggered the alarm in the house next door.
The person who pressed the button could not have committed the murder while simultaneously sounding the alarm. They can therefore be eliminated from the list of suspects. So far nobody has confessed, but thanks to dactyloscopy you can still reveal their identity.
Instructions: Pick up the square with the partial print and see how it overlaps with the fingerprints of the suspects. When you find the print which matches the partial fingerprint, you will have the fingerprint of an innocent person. Mark it in the app by answering question #1.
Dactyloscopy - complicated word, complicated definition. Basically, it means fingerprinting. And the definition? Dactyloscopy is the science of dermal papillary lines on the fingers, palms and soles. The course of these lines is so characteristic for everybody that fingerprinting is a highly useful method for identifying individuals, especially in criminology.
People leave dactyloscopic traces behind on objects and materials that they have touched or held. The human palm is permanently slightly sweaty and so leaves traces behind with every touch. These can be made visible using various methods of physics or chemistry. Thanks to dactyloscopy, we are then able to compare the fingerprints of the perpetrator with fingerprints of suspects. This method is also used to identify corpses of unknown identity, or individuals who do not wish or for some reason cannot reveal their identity.
Your Fingerprint = Your Signature, or You Need Marks to Identify Somebody!
Marks are small irregularities in the spacial course of the papillary lines, which represent the individuality and originality of a drawing with their specific positioning in the given pattern, thus enabling personal identification. Comparison of dactyloscopic traces and individual marks is conducted using a dactyloscopic comparator. The examination method is known as marking, and is different in every country.
In the Czech Republic the number is determined as follows:
· Usable print – number of marks is higher than 10
· Partially usable print – 7 to 9 marks
· Unusable print – 6 and fewer marks
Does a fingerprint collection exist? Yes! Two types of collections are kept for the purpose of dactyloscopic identification, and these are:
a) The Central Institute of Criminology fingerprint collection
b) Regional fingerprint collections
The collections contain finger and palm prints , as well as prints from solved and unsolved cases.
· The origins of fingerprint examination date back as far as ancient China. Proof of this includes the document published under the title of “The Volume of Crime Scene Investigation—Burglary” from the Qin dynasty (221 - 206 BC). Fingerprints were also used in the provisions of various public and private documents.
· The first person to use fingerprinting in practice was William James Herschel in India in 1877. He used dactyloscopy to check those receiving military pensions. The soldiers had been going for their payments twice.
· Jan Evangelista Purkyně studied papillary lines in our country.
Points of interest:
· No two individuals in the world have absolutely identical papillary line patterns.
· Papillary lines are irremovable, and remain the same throughout our lives.
· Did you know koala bears have fingerprints too?
Trichology, station no. 2
Mini-story: One of Dr Rush’s friends brought her a cute little kitten as a surprise to the gala. He or she hid it in a bedroom on the second floor so that Dr Rush would not find it before it was time to give out gifts.
A witness claims that at the time the alarm sounded he saw somebody on that floor coming out of a bedroom to see what had happened. Unfortunately he or she got lost in the crowd of guests and the witness did not see who it was. The forensic team found a large quantity of trichological samples in the kitten’s bed. These must be compared to the samples of the suspects in order to find an innocent party.
Instructions: A sample found in the kitten’s bed is placed on the sliding picture, while samples from all the suspects are fixed. By sliding the sample from the kitten’s bed you can compare the fibers and hairs found on the suspects. Finding a matching picture means you have found an innocent party, who was playing with the kitten at the time of the murder and could not have harmed Dr Rush. You can cross them off the list of suspects. In the app answer question #2.
Trichology – sounds interesting, right? It’s the examination of animal and human hair as part of police investigations. It is reported that up to 75% of traces found at crime scenes are of a trichological nature, largely because the material is highly durable (even the hair of mummies from Pharaonic tombs can be studied relatively well). However, trichological analysis is relatively time-consuming and financially and methodically demanding, so it is only used in cases where there is a lack of other traces.
A certain Professor Wheeler from London became the first to start researching hair care and the causes of loss of hair in 1860. The Institute of Trichologists was founded in London in 1902 and trichology, the science of hair and the scalp, came into being. Its name is derived from the Greek word trichos, meaning hair.
The human body is covered by around 5 million hair follicles, the “seeds” of future hairs. Every hair has two basic parts – the root (follicle), embedded in the skin, and the shaft, which protrudes from the skin.
Hairs differ in structure according to which part of the body they emerge from. Pubic hair (from the genitals), axillary hair (from the armpits), beard hair and eyelashes can easily be distinguished beneath the microscope.
Material for trichological examination is sought at the crime scene and places where the appearance of suitable samples for comparative analysis are expected (car seats, animal cages, car trunks...). The traces are sought visually, sometimes oblique lighting is used or a light source with a certain wavelength (ultraviolet, infrared). In cases when the situation demands it (for example serious criminal acts), trichological traces are documented photographically before they are collected. Numerical and graphical markers or pointers (paper arrows) are used in photo-documentation. During collection, just like for other biological traces, contamination and the transfer of one’s own biological material must be prevented – gloves, masks and protective clothing are used, and the collection is made with tweezers.
A relatively large amount of information can be detected from trichological material (TM). Several basic parameters are usually established:
1) if the material is biological or not,
2) the origin of the biological material (human, animal, plant),
3) for animal TM – determining what kind of animal it comes from,
4) In the case of human TM – we find out what marks the material bears and compare to reference samples.
If the hair has been preserved complete with its follicle, serological examination can determine its owner’s blood group, and we can conduct genetic examination (for instance we can find out whether it belonged to a man or a woman, the ethnic origin of its owner and much more besides). Chemical analysis reveals the presence of various elements (heavy metals, combustion accelerants) and traces of drugs (some drugs can be detected several months after their use). Microscopic examination can detect abnormal changes to the hair structure – morphological and metric characteristics are evaluated (shape, texture of hair, presence of parasites, mechanical damage). During microscopic examination we compare various hair samples (for example from the victim, the murder weapon, suspect’s car seats and so on) and determine the degree of concordance in the comparison.
Example of questions which trichology can answer:
Is the hair damaged? What caused this damage?
Can external factors be identified which affected the hair, and when? While alive, after the hair was pulled out, after death? Does the trace have any significance to the case?
Can anything be said about the time sequence of the change to the hair? (Relating to crimes - was the victim first suffocated and then taken away somewhere, or the other way around?)
Can it be determined whether the hair was plucked from a living or dead person?
DNA fingerprinting, station no. 3
Mini-story: A small quantity of the killer’s skin was found beneath the nails of the victim, as Dr Rush scratched them in her fight for life. This skin serves as a sample for testing using genetic fingerprinting techniques. The skin is not of a high enough quality to directly attribute it to a specific person, but we can discover who could not possibly have left it. Previous testing did not eliminate any of the first group of suspects. Testing the rest of the suspects is now up to you!
Instructions: Compare the STRs of the individual suspects (a pairs of boxes with numbers in 4 rows) with the STR from the crime scene (a trio of boxes with numbers in 4 rows).
When you find a suspect whose STR does not correspond to any of the colored boxes with numbers from the crime scene, you have found an innocent party!
In the app mark their name at question #3.
Use of DNA in criminology
What is a DNA trace?
A trace of biological origin (meaning from some kind of organism, not necessarily a human, it could be a plant, animal or bacteria) which was found at the crime scene and provides a certain lead towards solving the case.
Become more closely acquainted with DNA
The main function of DNA is the preservation and transfer of hereditary information through genes. These are what we call protein coding DNA segments.
To put it as simply as possible: DNA is a kind of cookbook for cells, so that they know how to cook up all the proteins they need to work.
In higher organisms, however, genes only make up a fraction of overall DNA. For people it is around 1.5%. The remaining part of DNA consists of so-called non-gene areas. Here we can find leftover genomes from various viruses, regulation areas (which make work with DNA easier for the cell) or places which have a protective function (protecting the rest of the DNA from damage). The function of most areas of DNA is unknown to us. That does not mean, however, that we cannot make use of it
Nowadays STRs, or short tandem repeats, are most often used in forensic sciences. These are areas with 2-6 nucleotide motifs ([ATC], [CTGA], [ATTCG] etc.), which repeat several times in the given location (for example ATCATCATCATC – here the motif is repeated 4 times). A large quantity of STRs appears in human DNA. Furthermore, two copies appear in each individual (in the chromosome from the mother and the father).
The magic in the method lies in the fact that the number of repeated motifs in STRs varies greatly from person to person. If we determine the number of repeated motifs in a sufficient quantity of STRs (usually 16-19 STRs), we get a unique combination, using which will help us tell two individuals apart. This is what they are used for in criminology – to identify individuals. Obviously STRs will be more similar in people who are related, but even so this method distinguishes so well that we can tell any two people on the planet apart (with the exception of identical twins, who have 100% identical DNA).
Collecting DNA traces
Collection of traces takes place at the scene of the crime and places connected with it. There are various kinds of trace – visible (a pool of blood), visible in certain conditions (special lighting, chemicals – e.g. urine, sperm) and latent (invisible, they are taken on the basis of the experience and intuition of the investigator).
The collection is conducted so that the investigator does not contaminate or destroy the traces (they have protective clothing, gloves and a mask) and is carried out in places where material is expected to be found. Visible traces (see above) as well as latent ones are taken from places where they might be but cannot be seen (tissue is taken from beneath the victim’s nails, cigarette butts, caps, clothing, the murder weapon etc.). Collection either takes place in a laboratory or at the crime scene. Traces are collected in a laboratory if they can be taken from the crime scene in a bag (secured against contamination), for example cigarette butts, hairs, the murder weapon and so on. Collection at the crime scene is carried out using a sampling tampon (swabs are made from the vagina, mouth etc.) and the tampon is taken away in a bag.
How DNA traces are examined
DNA is isolated from the traces, propagated (using the PCR method), DNA profiles are created (most often based on STR) and these are then compared. STR profiling is used most frequently, but other methods (for example mitochondrial DNA analysis) can be used if the DNA is of very low quality.
One important thing is YOU CANNOT TELL FROM DNA HOW OLD THE TRACE IS!!!! That means you are only able to answer which DNA can be found at the crime scene, and not how long it has been there.
The forensic genetics method, known as DNA fingerprinting, works with non-gene areas – that is segments without any functional significance. The English scientist Alec Jeffreys discovered it on 10 September 1984 at 9:05 a.m. Jeffreys was interested in the variety of human DNA and discovered certain patterns which repeated, but appeared in different people in different forms.
Points of interest
The first case (from 1986) to be solved with the aid of DNA was in 1987. It was that of the rape and murder of two young girls in Leicestershire, Great Britain. Both crimes shared similar characteristics and examination of the perpetrator’s sperm revealed that he was a man with blood group A (about 10% of the population). Richard Buckland, who had been seen near the crime scene, confessed to the first murder. However, DNA testing of the perpetrator’s sperm revealed that although both girls had been raped and murdered by the same man, that man was not Richard Buckland.
The police therefore ordered a mass collection of blood and sperm samples from all the men in the entire county (which, incidentally, would be unthinkable today!) and used them to make DNA profiles. However, none of the men who did not have an alibi corresponded to the perpetrator. The police then broadened their search to include men who did have an alibi, but also without success. Sometime later Ian Kelly boasted in front of colleagues that he had given his sample instead of his friend, Colin Pitchfork. One of Kelly’s colleagues informed the police, who arrested Pitchfork, whose new DNA profile proved that he was the killer.
Trace evidence, station no. 4
Mini-story: The murderer could not be recognized from the security footage partly because it was raining heavily. Although this destroyed many traces at the crime scene, a number of footprints remained in the wet soil around it. Technicians quickly made several casts which need to be compared. However, all the visitors of the event received footwear for their voluntary work. Thorn the gardener and Dotty the dentist cannot be eliminated because they worked around the house and too many of their prints were found. But who do the other prints belong to?
Instructions: Technicians for CSI iQLANDIA took plenty of footprints from around the crime scene. The shoe that does not have a print here belongs to an innocent suspect who can be eliminated. Don’t forget to cross them out by answering question #4 in the app.
Trace evidence is a forensic field concerned with examining the prints of footwear, feet, tires and the like. These can be two or three-dimensional.
The prints are categorized:
1. Footwear and barefoot prints
- A flat bare footprint is called a plantogram
- The shoe sole, heel and tread are expertly examined
- This examines, for example, how the foot is planted, the length of stride, width of gait or position of the feet. Everybody steps with different force, and steps differently when they are running or when they are walking. The depth of the footprint is also influenced by our weight.
3. Vehicle tracks
- This includes tracks from tires, caterpillar tracks, and even unusual vehicles, such as sleds. For examining tires, their size, wheelbase, track width, shape and pattern are important.
4. Other prints
- Marks left by teeth, ears, lips, elbows and other body parts fall into this category.
Prints can be provided using several methods:
In the original - that means that part of the object which made the print (or even the whole object) is removed.
Casting - only possible when the prints have depth. Plaster or other materials are used to make the cast.
Photography - the two or three-dimensional print is photographed. A ruler must always be placed by the print.
Removing on dactyloscopic film - flat prints are taken. The method is similar to fingerprinting.
Baking on a thermal instrument - can be used for prints where rubber came into contact with paper.
Electrostatic dust recording - the print is transferred to foil using dust particles charged by a high voltage.
This method started to come into use at the start of the 19th century thanks to the former galley slave, criminal, later policeman, secret agent and last but not least the first chief and founder of the Brigade de Sûreté, Eugène François Vidocqovi.
Points of interest
Did you know that prints must often be made visible before they can be recovered? This can be done with the right light (e.g. oblique lighting), dust which disperses over the print, or chemicals.
Identikit, station no. 5
Mini-story: Three witnesses saw somebody running away from the event. They only caught a glimpse in the darkness, but each witness saw the face of the suspect for an instant as a passing car lit up his face. At that moment the alarm sounded and we know that the culprit was committing the crime at that moment. The fleeing person is certainly suspicious, but cannot be the murderer whom we seek.
Instructions: Carefully read the statements of the witnesses and put together a portrait of the mysterious runner. Each witness remembers a different part of the fleeing person’s face. Find the correct facial features the witnesses describe and place them label down on the right-hand side of the “identification board.” If you read carefully, you will assemble the face of one of the suspects. Which of the portraits does it most remind you of?
Witness A: I couldn’t see much at that speed but I know he had eyebrows like Brezhnev. You know, really bushy eyebrows!
Witness B: I quite like beards on a man so I know for sure he had a bearded chin. The rest of his face was hidden by a branch or whatever it was.
Witness C: It was definitely a guy and he wasn’t that old. He had a balaclava on, or he was shaven-headed or wearing a cap! Hard to say.
Have you ever really scrutinized somebody’s face? Whether you have or not, bear in mind that yours is unique and easily recognizable to a real expert. And which forensic science will recognize your face? Portrait identification! However, it is not always as easy to form an image of the suspect as it might seem. Not only victims but also witnesses often lack the ability to distinguish details of the face or body of the perpetrator, even in the calm of the investigation, never mind the stress of the act. The weather, lighting and distance all play a role.
If there are multiple witnesses, a good detective will compose a portrait according to each of them separately, so they do not influence each other. If more pictures of the same perpetrator are created, they are all published individually.
Portrait identification is used while:
searching for wanted and missing persons
Identifying persons (living and dead)
Points of interest:
No two people in the world have identical physical measurements.
The measurements of some bones do not change after reaching a certain age.
Potraiture is the oldest method of identification.
Alphonse Bertillon, an official form Sürete in Paris, made a significant contribution to the development of the method: in 1879 he developed and brought into practice a method of registering people on the basis of eleven bodily measurements (so-called Bertillonage), which were recorded on one card.
An example of an official description, or what we distinguish during the portraiture of a human face:
The shape of the face – we evaluate its color, the shape of head, fullness, freckles and other distinguishing features, bone structure...
Hair– we evaluate its color, shape, abundance, cut and other distinguishing features.
Facial hair – we evaluate its thickness, growth, shape and cut.
Forehead – we evaluate its height, width, angle, arching and wrinkles.
Eyebrows – we evaluate their shape, angle, size, distance, thickness and color.
Eyes – we evaluate their color, shape and distinguishing features.
Ears – we evaluate the shape of the earlobes, their position on the head – it is known that it is practically impossible to find two people with matching ears (even identical twins have different shaped ears)
Nose – we evaluate the width and height of the ridge and base, root, tip and various distinguishing features.
Teeth – we evaluate their completeness, color, distinguishing features – a highly significant identifier.
Chin – we evaluate its shape from the front and the profile.
Criminal ballistics is the science that deals with the mechanism of the shot, the movement of the projectile in the barrel of the gun, the trajectory of the projectile as it flies towards its target, and the effects of the projectile on the target. Research areas of ballistics can be divided into three basic groups:
- The first research group is firearms that can be used to deliver a projectile to a target.
- The second group consists of ammunition (projectiles) of all types and their individual parts, especially fired bullets and cartridge cases.
- The third group consists of objects hit by a gunshot and post-gunshot fumes.
The main tasks of ballistics include identification of the weapon used by the perpetrator, known as individual identification. The components of the weapon that are in contact with the bullet and cartridge when fired leave so-called markers (specific marks) on their surface, which are a clear reflection of the micro-porosity of the contacted surface. The examination of firearms is based on the mechanoscopic traces produced on the surface of bullets and cartridges when they are fired. This examination was already one of the basic tasks of expertise during the First Republic.
[Hand] Turn the carousel and observe the comparison casings and the sample found at the crime scene under a magnifying glass. See which ones match.
[Eye] Compare the markers (small firing pin marks) on the primer of the cartridge case
[Owl] Each component of the weapon leaves unique damage marks on the cartridge case and bullet when fired. As a result, by comparing the shell casings recovered at the scene to those from the suspect weapon, the weapon used in the crime under investigation can be identified.
Mechanoscopy is a branch of criminology that deals with the identification of tools used by the traces they leave on objects that have been attacked. Each tool used has its own specific characteristics which enable its identification on the basis of the traces it left on the object attacked. Thus, different traces are left by cutting, drilling, chopping and other tools.
The work of forensic experts is based on the comparison of these traces.
The mechanoscopic trace left by the tool at the crime scene is compared with a test trace. At least two different traces from several crime scenes are compared and evaluated to see if they match.
No tool is absolutely smooth. Each has its own specific irregularities introduced during manufacture or modification. It is absolutely impossible for the irregularities in two objects to be exactly the same. And the task of the specialists is clear: to find identical markers and to deduce that the objects (traces and object, traces and traces) match.
[Hand] On the carousel, select the type of cylinder insert by rotation and see what it consists of. In the video in front of you, observe the working principle and various types of protection.
[Owl] Simple locks were used as early as 3000 BC by the Babylonians and Egyptians, but the cylinder insert as we know it today was not developed until 1865 by the American Linus Yale.
Odor traces can be obtained by using a syringe to draw air from the immediate vicinity of the crime scene. A more recent method of securing traces is to absorb the odor in a suitable absorbent material. Air is pumped through a tube filled with absorbent material (molecular sieves, activated carbon, thin metal foils).
A special fabric is also used for this purpose, which has a considerable absorption capacity and allows the odor to be absorbed. The fabric is applied where an odor trace is expected to exist and absorbs it. Once sealed, an odor trap is made. Comparative samples of human odor can also be obtained in this way, for example by placing the textile under the armpit, by inserting it behind a piece of clothing or by having the person sit on the textile.
Assessment and evaluation
The use of service dogs to assess and evaluate scent traces is typically a subjective method. The dog can be used both for tracking scent traces, for example in the search for a fresh (“hot”) trace, and for assessing seized scent traces and comparative materials.
When assessing the submitted scent traces, the dog sniffs the traces, “evaluates” them and marks the same scent traces or traces and comparative materials in a specified manner. This marking is done by the dog, according to its training, either by barking or by lying down next to a matching scent trace.
[Hand] Would you make a good police dog? Squeeze the bottle and smell its narrowed neck at the same time. Can you identify the odor trace in the bottle?
[Owl] A German Shepherd has up to 200 million olfactory cells, a human has only 5 million. Even so, our sense of smell is in some cases better than that of animals. For example, we can detect the smell of rotten fruit before dogs can. For our ancestors, it was vital to recognize the edibility of fruit by smell, but not for dogs.
[Hand] Sit facing each other and position your heads so that they are equidistant from the mirrors and merge.
[Eye] If you manage to do this, you will see before you, for example, your own forehead and nose, and your partner’s eyes and mouth.
[Owl] When compiling a portrait of a wanted person on the basis of witnesses’ testimony (identikit), the facial image is composed of individual segments. The eyes, nose and mouth are among the most prominent features of the face and determine much of its appearance. Any change in them will significantly alter your appearance and expression.
You are currently at the desk of Jan Novák, CEO of a successful technology company. Mr Novak’s competitors have hired you to steal the secret plans for a new product that is set to revolutionize the range of electric cars. Using the clues on the desk or in the drawers, can you guess the code to the hidden safe?
[Hand] Play burglar and see how hard or easy it is to crack a four-digit numerical password.
[Owl] Did you know that one of the most common password creation mistakes is using personal information?
A policeman has managed to catch the perpetrator of a bank robbery and needs to bring him and the loot to the city police station. However, there is a river in their way, no bridge across it and only a small boat. The policeman has to ferry the thief, the bag of loot and the gun across the river. The boat can only fit the policeman and one passenger (it’s a really big gun and a big bag of loot). If the policeman leaves the thief alone on the shore with the loot, the thief will escape with the loot. If he leaves the pistol and the thief alone on the shore, disaster strikes. How can the policeman get to the other shore with the whole load?
If the last name left on your card is that of the gardener Miranda Thorn then congratulations! You are a true detective and have helped us solve the case! She is the prime suspect!
At the age of 35 Dr Rush was tired of waiting for innovative scientific progress, and so decided to pour all her energy into a classified project for large-scale water purification equipment. However, by happy coincidence she invented a perpetual motion machine. She realized what this could mean for the world. She was so afraid it would be misused that she destroyed it and kept the plans for its construction on her person at all times. She confided all this to just one friend - Thorn the gardener. However, instead of being pleased for her, she began to discourage her from the whole project. On the one hand she saw in the discovery the chance for greater protection of nature, on the other she was afraid of nature’s destruction with the building of new power grids, expansion of industry, decline of humanity and war caused by the envy of neighboring countries. Despite her gentle nature and their friendship, she therefore decided to commit the horrific act and she murdered Dr Rush.
And why did Stoker set off the alarm?
Stoker set off the alarm because he saw the murder of Dr Rush with his own eyes. However, he was afraid to admit this to the investigators, in case suspicion fell on him because of the property disputes between himself and Rush.
And why did Little run away from the crime scene?
Stephen Little wanted to be constantly in Dr Rush’s vicinity, so he crept into her event to become reconciled with her. When security saw him, they gave chase and he ran away.