Searching for stains on exhibits and preparation of stain material
Trace materials such as blood, saliva, sperm, hair and epithelial skin particles suitable for molecular-genetic analysis are recovered at many crime scenes, other locations related to a crime and from individuals involved in the crime, i.e. victims and/or perpetrators. These stains contain cells that can be matched to individuals by means of DNA analysis.
Microscopic examination of stain material
One of the challenges for experts in “human evidence” is the development of specific methods of forensic DNA analysis. Thanks to progress in this area, it is now possible to examine trace material that would have been regarded as unsuitable for evaluation just a few years ago. Examples include shed hairs or skin particles left behind when the crime was committed.
Dyed buccal epithelial cell with cell nucleus, 60x magnification
From stain analysis following terrorist attacks to the matching of body parts to the evaluation of blood-distribution patterns, KTI Forensic Science Institute experts support the investigation process and prepare expert reports for submission as evidence in court.
Regarding casework a further focus lies on the generation of DNA profiles for the national DNA database (DAD).
DNA isolation
Results obtained from the analysis of stains and individuals are forwarded to the Identification Service and entered in the DAD according to the DNA legislation. Matching profiles in the database provide valuable leads for investigators and have now become an integral part of the fight against crime. Nowadays DNA profiles can even be matched among DNA databases of several European nations which can provide investigative leads for cross-border crime.
Electrophoresic separation of DNA fragments
In order to maintain the extremely high evidential value of the analyses and to ensure the use of even the information contents of minimum amounts of stains special methods and strategies for evidence preparation and the prevention of cross-contamination are crucial. These but also new developments in methodology are presented and discussed at national and international forums. Consulting in matters such as preparation of draft legislation as well as involvement in large-scale operations such as mass disasters are also part of the work of the experts in human evidence at the Forensic Science Institute.
Analysis and typing of a stain