The notion of forensics

Forensics is a science that uses as an essential tool the observation and interpretation of physical evidence, with the aim of resolving offenses.

Forensic science includes the following areas of similarities such as: crime, pathology, biology, toxicology, forensic dentistry, forensic anthropology, forensic psychiatry, while other parts develop on branches such as geology and microscopy.

In the first decades of the 19th century forensics developed within the framework of medicine, however, its active implementation in police investigations began very quickly.

Division forensics

Forensics can be divided:

– according to the scientific fields whose method is applied (forensic physics, forensic chemistry, forensic biology, forensic mathematics)

– in areas where he applies his methods (human forensics, social forensics, digital forensics, forensic engineering)


Trasology is a branch of forensics that represents the science of traces found at the crime scene. The main trace is every trace of organic or inorganic origin at the very place of the commission of the crime. The role of material traces in the clarification of criminal offenses consists of the corpus delicacy data evidence of guilt), information on modus operandi (own way of committing a crime), linking the suspect with the victim or victim, linking the perpetrator to the crime scene, identifying the suspect, identifying the object.

Traces are divided into:

Traces of temporary character (quickly disappearing or easily changing, found by the person who first finds himself at the crime scene)

Traces of characteristic appearance (fingerprint, stain, fracture, swabs, footprints, clothing traces, traces of car tires)

 Conditional clues or traces resulting from the action or as a consequence (light, smoke, fire, vehicle, body)

 Contact traces (murder, fire, organic, inorganic, natural)

Criminalistic ballistics expertise

Criminalistic ballistics in the broader sense includes all firearms surveys. To be able to talk about such expertises, we need to look at the clarification of terms. The science of science as a science discipline is divided into:

 Internal ballistics that studies the burning of gunpowder in the firearm tube, the movement of projectiles through the firearm tube, the construction of the pipe, and the speed of the projectile from the firearm tube.

 External ballistics that studies the movement of projectiles through the air using the Newtonian Mechanics Laws.

When everything is reduced to a general term, criminal ballistics is an area that studies, finds and improves the most appropriate scientific and technical means and methods in order to find and secure material traces in order to solve and clarify criminal acts committed by firearms.

Expertise of traffic accidents

Expertise on traffic accidents can be divided into:

 Forensic medical practitioners practicing forensic medicine, where they make special reports on the performed expertise,

 Traffic and technical issues include the correctness of the vehicle, the condition of the carriageway, the speed of the car,

 Criminalistic-technical involves determining the location of contact of two vehicles, vehicle contact and pedestrians, vehicle identification, identification of a person.

Traces resulting from traffic accidents can be divided into the following:

 Tracks of wheels on the surface

 Substrate tracks

 Tracks on the vehicle and traces in the vehicle

Traces of vehicles on the victim

Traces of the victim on the vehicle

As for the brakes of the vehicle braking, the explanation is as follows. Between the wheels and the substrate there is a large force of friction opposite to the direction of the vehicle’s movement. Such energy, in the form of heat, passes to the tires that are rapidly heated and disintegrating. Over the tire, and on the surface are visible traces from the moment of braking when they are most pronounced, until their break, when they go into the traces of blocking or disappear. Based on the length of the brakes, it is possible to estimate the speed of the vehicle.

The length of the trail is measured from the point where the trailing part of the track begins, or when the start has started, to the axis of the front wheels of the stopped vehicle.

As far as the traces left off from the vehicle are concerned, such traces can be classified as traces remaining at the scene of the accident or on the victim, and serve to determine the type and type of vehicle. These are: paints and varnishes, vehicle parts, pieces of glass, paint with sheet metal, etc.

In the case of vehicle traces and traces in the vehicle, these are brushes of color from another vehicle or other object, traces of blood, tissue, clothing, hair, as well as traces of papillary lines (fingerprints) that are most common in the scene of any offense.

Restoration of destroyed marks on metal objects

Restitution or Latin-speaking return to original state is an artificial example that restores the destroyed marks to a state that allows them to be read or deciphered in their original state. This expertise must be accompanied by photo documentation. The marking is subject to motor vehicles, firearms, some musical devices.

The detection of destroyed labels can reveal criminal activities, while destruction is done by scraping, metal melting or destroying marks by mechanical blows. The criminalistic importance of restitution of destroyed numbers has the probative value of the offense and operational significance.

As far as labeling of metal objects is concerned, they are done by marking the markers with numerators, marking with electric stylus, marking metal objects by engraving and marking metal objects by casting.

Perhaps one of the main things about this topic about the restitution of labels on metal objects, and it is very important to mention the masking of the mark on metal objects. Marking of labels on metals is done in the following way:

 By swiping the original mark with a thin layer of lead or tin

 A falsified tag is imprinted on that layer

 It is then coated with color until the original number is destroyed

Regarding the restitution of destroyed markings on metals, the process consists in preparing for restitution as in the restitution method itself. When preparing for restitution, surfaces with the destroyed mark are irradiated with organic solvents. Fats are removed when using the restoration methods. There is a method of chemical corrosion, methods electrochemical corrosion, magnetic powder method, intensification method.

DNA identification

DNA or translation of deoxyribonucleic acid is a method that we use to detect the perpetrator and identify the face in general. Each cell of the human body possesses genetic material, so the slightest trace can help us for identification purposes.

After the sample is examined, a small portion is taken that will be used for the taking and analysis of genetic material. Evidence must be absolutely clean, so forensic agents must apply protective gloves and the like to avoid contamination of the traces. Extracting biological material using a DNA analysis of the molecule consists of:

 Collection of samples of biological traces

 Taking reference biological samples

 Isolation of DNA molecules from biological material

 Determination of the quantity and quality of DNA molecules in the isolate

 Enzymatic analysis of the isolates

 Obtain DNA profiles from biological samples

 Comparison of the obtained DNA profiles and biostatic processing of results

 Interpretation of results and giving expert opinion

The most common biological samples encountered by the forensic DNA laboratory are: Blood samples, Seeds of fluid, Saliva, Hair, Skin, Teeth, Bones, Muscular tissue, Various other tissues and body fluids.

Experimenting with narcotic drugs

Narcotic drugs (frank drugs) represent natural or synthetic organic products whose use of persons can create addiction states that inevitably lead to:

 Damage to health

 Endangering of human integrity in physical, psychological and social terms.

Narcotics are pain-relieving substances. They have a debilitating effect on the central nervous system and cause drowsiness. Regular taking of narcotics leads to physical dependence. In this topic we will mention only some of the most common drugs and give a brief explanation for each of the above. These are:

 Herion (obtained by chemical processing of morphine, it is easily soluble in water, has a stronger effect than morphine from two to two times per trip. It is from Afghanistan, the “Golden Triangle” or South America. The heroin purity is 35%, while the other 65% They make milk powder, starch, talc, gypsum, baking soda, quinine. The short-term effects of heroin are heat, facial tint, skin redness, difficulty speaking and dry mouth. blood vessels, liver disease, lungs, death.)

 Marijuana (Marijuana is a dried leaf of cannabis, which eliminates thicker veins and stems. The leaves are crumbled and marijuana drugs are obtained. It occurs in the form of a cigarette. The effects of using large doses of marijuana are memory problems, accelerated heart rate, panic attack and paranoia, increased need for food. The effects of prolonged use of marijuana are permanent brain damage, cardiac disorders, increased blood pressure, carcinogenic pulmonary disease, esophagus.)

 Hashish (hard, resinous, brown or greenish mass, which is mechanically separated from the flowering tips of the Indian cannabis. It is also dipped in a solution of alcohol, which produces a resinous material. It occurs in the form of square plates, powdered packagings packed with paraffin and liquid form of a sticky substance of dark green color.)

 Cocaine (Pure cocaine is obtained from the leaves of the “divine plant” of the Ekathroxylon coca plant since the 19th century. The coca plant grows in South America / Colombia, Bolivia and Peru. The effects of cocaine use on the user are increased alertness, absence of hunger and fatigue, and temperature. As health problems can occur cardiovascular in the form of heart attack, neurological in the form of headaches and stroke and stomach. As for the cocaine pack on the street is sold as a fine white powder, a jargon called “coca”. The starch is added to powder , sugar, other drugs such as procaine or amphentamine synthetic drug spid.Cocaine and crack are combined with heroin and this is called a speedboat of a jargon.)

 Identification of the narcotic drugs is performed by Screening tests (Color tests, Microcrystalline tests, Immunochemical tests), Using shredded dogs, Chromatographic methods / THC, GC, HPLC, … /, IC spectrophotometry, Mass spectrometry / MS / GC / MS- spectrometry, Neutron Activation Analysis / NAA /.


Author: Marko Kraljevic