General: an expert in Forensic Weapon and Ammunition Examination identifies, typifies, classifies and describes portable firearms and the ammunition intended for such weapons according to the Weapons and Ammunition Act.
Comparative bullet and cartridge case examination
During the comparative bullet and cartridge case examination, an examination is conducted into microscopically small mechanical damage (weapon marks) on components of ammunition (bullets and cartridge cases) and cartridges. These marks are created when shooting or chambering ammunition in a firearm. The marks are characteristic of or particular to the firearm used and are consequently, highly indicative.
Connections can be established between each of the examined components of ammunition and/or between those components of ammunition and a firearm by comparing the weapon marks on bullets, cartridge cases and cartridges with each other. A special form of comparative bullet and cartridge case examination is an examination of the found ammunition components with a larger collection of stored bullets and cartridge cases from various shooting incidents.
During the comparative bullet and cartridge case examination, the expert identifies relevant weapon marks and compares these with the aid of a comparison microscope equipped for this purpose. The discovered similarities and differences are recorded and interpreted. The latter leads to a statement as to whether the findings are in line with the hypothesis that ammunition components had been discharged in the same firearm or that a given individual firearm had been used or that it was not used.
Weapon-technical examination for the purpose of reconstruction
During a weapon-technical examination, a weapon is examined for mechanical operation, defects and failures for the purpose of reconstructing the causes of a shooting incident. The condition and construction of the weapon are considered while taking into account the actions alleged to have been performed with it. These acts largely concern the possibility of accidental firing during throwing, falling, hitting or struggles.
The weapon is tested for sound operation. The examination consists of a thorough (microscope) inspection for damage, signs of wear and tear or missing components. The safety mechanisms that should be present have to be checked, followed by shooting tests and/or experiments that can recreate the acts that have been suggested as possible scenarios. The expert is able to establish, by means of inspection, assembly or disassembly an analysis of faults and failures, and an estimation as to whether there is any true basis for the proposition that the examined weapon fired by accident.
The forensic ballistics examination
The forensic ballistics examination consists of all four phases of ballistics: internal, muzzle (or transitional), external and terminal ballistics. The latter two are particularly relevant in connection with the direction of the shot, determining the firing distance and the effect of the bullets on targets that have been hit.
Experiments are conducted during ballistics examinations with the aim of evaluating the hypotheses proposed by the commissioning party concerning the shooting incident. The questions that can be asked are highly diverse in nature.
- The expert can determine the projectile velocity (for example with a Doppler radar or a light barrier) and precision of a weapon-ammunition system.
- The firing distance can be evaluated by reconstructing the available data from the crime scene (for example, the spread of buckshot).
- Reconstruction of projectile trajectories.
- The potential for fatal injury can best be evaluated by performing test shots on calibrated tissue simulators.
The expert has to be capable and competent in the performance of all necessary experiments, perform them or have them performed, and to process and interpret the data of a significant number of measurements (statistically).
Legal domain: criminal law.
Boundaries of the field of expertise
Within the practice of the Forensic Weapon and Ammunition Examination field of expertise, the expert will come into contact with other fields of expertise, which are not part of his expertise.
The expert in Forensic Weapon and Ammunition Examination is aware of the possibilities and restrictions of the fields of expertise mentioned below.
The expert in Forensic Weapon and Ammunition Examination can assist and advise the police on site when searching, describing, recording, interpreting and securing marks and carriers of marks of shooting incidents on and around the crime scene.
In doing so, the expert will focus on:
- Advising on the approach of the technical examination, in particular bullet trajectory reconstructions on the basis of shot damage.
- Providing expert advice on safety with respect to the crime scene examination.
- Making weapons secure in unsafe situations (weapons from burnt out cars or under water).
- Proposing possible hypotheses or scenarios.
- Advising regarding potential forensic follow-up examinations.
Gunshot Residue Examination field of expertise
The Gunshot Residue Examination field of expertise concerns itself with:
- Ballistics on clothing and/or post mortem examination.
- Gunshot residue examination.
- Examination of the hand and /or sleeve used for shooting.
- Examination of micro marks on weapons and ammunition.
Pathology field of expertise
The Pathology field of expertise comprises the determination of the victim’s cause of death. It is also determined whether the identified shooting is the cause of the death.
Explosions and Explosives Examination field of expertise
The Explosions and Explosives field of expertise is primarily deals with the following investigation:
- Examination of intact factory produced and improvised explosive constructions.
- Identification of intact presumably explosive substances and possible raw materials for explosives.
- Research of explosions.
Usually, Explosions and Explosives examinations concern incidents other than shooting incidents.
The field of expertise of Assessment regarding the Weapons and Ammunition Act focuses on:
- Investigation regarding the section of law regarding Weapons and Munitions under which the firearm falls.
- Investigation regarding the grounds for exemption.
- All essential related extensive weapon-technical examination.