After the evidence found at the crime scene has been secured, it is examined by one of the police authorities' forensic investigation centers or the State Office of Criminal Investigation in Düsseldorf. The police use state-of-the-art investigation methods to gather evidence.
In addition, external and independent experts are also commissioned to carry out investigations, who then act as expert witnesses in court.
Fingerprints are still an essential piece of evidence. Dactyloscopes, which are specially trained employees, compare fingerprints with the fingerprints of suspects. This comparison is made possible by an identifying evaluation of the individually characteristic and unchangeable features of the skin ridges on the palms of the hands. Years ago, so-called fingerprint sheets were laboriously and very time-consuming evaluated and recorded by the experts.
Today, they are scanned electronically on a computer and compared with the fingerprint sheets and crime scene evidence already available in digital form. This process is known as the Automated Fingerprint Identification System (AFIS). In AFIS, an independent nationwide comparison of the stored fingerprints of all unsolved crimes with all fingerprints stored for the purpose of the identification service is carried out. Electronic delivery of the data and automated searches enable immediate comparison of the database and the speed of the trace comparison is now multiplied.
If victims or witnesses have observed an unknown person in connection with the commission of a crime or if the image material available to the police of a known suspect no longer corresponds to his current appearance, our experts are just as much in demand as for the facial soft tissue reconstruction (digital thanatopraxy) of unknown dead bodies: The employees of the "Visual Search Aids" task force of the State Office of Criminal Investigation are immediately available to the district police authorities for the creation of the composite images and image montages required for search purposes.
The task force uses the tried and tested principle of associative memory via image inspiration and photomontage and is extremely successful, with success rates of between 25 and 30 percent.
Microtraces are all forms of object traces that, due to their small dimensions, can only be assessed by the human eye using optical magnification through magnifying glasses and microscopes.
These traces or their transmission in the context of a crime cannot be deliberately manipulated by the perpetrator. This enables a criminalistic analysis of crime sequences and leads to a high level of informative value.
Textile microtraces ("lint"), which detach from the surface of textile objects such as items of clothing and belong to the classic contact transmission traces, but also hair traces of human and animal origin, make up the largest proportion of this group of traces, which can be detected on the respective trace carriers as a result of various crime events. Their examination and forensic evaluation with regard to their forensic relevance is the main task of the official experts working in this specialist area.
Fiber traces also include so-called "melting traces", which are often found in the interior of cars after serious traffic accidents and can help to clarify the dynamics of the accident or to identify the driver of the vehicle involved in the accident, as the time of formation of such "melting traces" is reduced to the time of the accident.
Further material traces such as glass or paint splinters, which also occur in the form of micro-traces, are identified and comparatively examined at this site using current analysis methods such as FTIR or RAMAN spectroscopy and the associated state-of-the-art equipment technology.
In the Botany and Soil Traces department, micro-trace material can be found in the form of soil, dust and dirt deposits or wood particles, as can typically occur when windows and doors are broken open.
The determination of biogenic drugs, the consumption of which is becoming increasingly popular these days due to their easy distribution via the internet, is also part of our biological testing portfolio.
Blu-ray didn't always exist. Almost all video recordings are processed and analyzed at the Forensic Science and Technology Institute (KTI) of the NRW State Office of Criminal Investigation. For example, video sequences can be edited there, shaky sequences stabilized and individual images created.
Very long videos from surveillance cameras, for example, are automatically scanned and reduced to the essential sections. Relevant sequences can then be analyzed in their original length. This can eliminate the need for hours of viewing a video recording.