A groundbreaking study has made it possible to extract way more information from fingerprints as evidence than what’s currently achievable.
A brand new study from the Department of Forensic Medicine at Aarhus University is the primary on this planet to research fingerprints on gelatin lifters using chemical imaging. This could possibly be crucial in criminal cases where current methods fall short.
Danish police incessantly collect fingerprints at crime scenes using so-called gelatin lifters. Unlike tape, these lifters are easy to make use of and are suitable for lifting fingerprints from delicate surfaces, corresponding to peeling wall paint, and irregular objects like door handles.
Once collected, the fingerprints are photographed digitally so that they may be processed through fingerprint databases. Nevertheless, traditional photography cannot separate overlapping fingerprints, which are sometimes found at crime scenes. Very faint prints are also problematic. In consequence, many fingerprints that might otherwise contribute to investigations unfortunately should be discarded.
A positive spray of solvent
An answer is presented in the brand new study from the Department of Forensic Medicine at Aarhus University, recently published within the scientific journal Analytical Chemistry.
“We’re presenting a way that has the potential to be integrated into the police’s traditional workflow. If this happens, more fingerprints from crime scenes could possibly be used and evaluated each visually and chemically,” says postdoc Kim Frisch, who’s behind the study.
The strategy is predicated on a way called Desorption Electrospray Ionization Mass Spectrometry (DESI-MS), which works by measuring the chemical compounds in fingerprints based on their mass.
“We send a really positive spray of solvent, consisting of electrically charged droplets of methanol. This releases and ionizes substances on the surface of the fingerprint on the gelatin lifter. The substances are then drawn into the instrument, where their masses are measured individually,” explains Kim Frisch.
DESI-MS was invented about 20 years ago and was developed for general surface evaluation. In 2008, it was shown that the technique could possibly be used for chemical imaging of fingerprints on glass surfaces and tape.
“But now we show that the technique can be used to research fingerprints collected on gelatin lifter, that are utilized by police in lots of countries, including Denmark. That is analytical chemistry utilized in a forensic context, and it has great potential,” says the researcher.
Revealing fingerprints where traditional optical imaging fails
Overlapping fingerprints pose a big challenge for investigators because they’re difficult to separate. The study shows that the brand new method may be used to separate overlapping fingerprints (Figure 2) and to boost faint fingerprints in situations where optical imaging fails.
To this point, the strategy has been tested on fingerprints lifted within the laboratory, however the researchers are actually testing the strategy on fingerprints from crime scenes. For this purpose, they’ve received fingerprints collected by the National Special Crime Unit of the Danish Police , and there are high hopes for the outcomes on the Department of Forensic Medicine.
Can we analyze gender, age, and dietary habits?
The strategy continues to be under development, and the researchers are actually focusing more on analyzing the chemical composition of fingerprints.
A fingerprint is way more than a novel pattern — it also accommodates quite a lot of chemical compounds from the one who left the print. These compounds include natural lipids, amino acids, and peptides secreted from the skin. Nevertheless, the fingerprint can even contain nicotine, caffeine, drugs, cosmetic ingredients, and potentially incriminating substances corresponding to lubricant from condoms and explosives which have been secreted through the skin or contaminated the skin upon contact.
Chemical imaging could potentially be used for profiling the one who left the fingerprint.
Many researchers around the globe are working to develop methods for this purpose — not only using the technique employed on the Department of Forensic Medicine in Aarhus. There are examples within the literature that fingerprints can reveal whether people have ingested or touched substances of abuse corresponding to cocaine, cannabis, and ayahuasca.
Studies have also been conducted with the aim of determining individuals’ gender, age, and lifestyle aspects corresponding to food plan, medication, and smoking from their fingerprints. The Department of Forensic Medicine continues to work on the study, supported by the Danish Victims Fundand ongoing for 2 and a half years, in an effort to maximise the data that may be obtained from fingerprints.
Research focused on practical application
The research is conducted in close collaboration with the National Special Crime Unit of the Danish Police because it can be crucial that the work is geared toward practical application.
To this point, the outcomes suggest that the strategy could possibly be utilized in practice.
“When the police collect fingerprints at against the law scene, the gelatin lifters can, in principle, be sent to the Department of Forensic Medicine, where we scan the samples. Nevertheless, the scanning process is time consuming, which implies that we’d not have the ability to research samples within the lots of, as we do with, for instance, blood samples. We expect that the strategy will probably be utilized in the longer term as a special evaluation in additional serious cases corresponding to murder and rape,” says Kim Frisch.
