Biological traces, like saliva, sperm or blood, are often found at crime scenes. Detectives also frequently find hair. This is no surprise, considering that every human being loses about 80 hairs per day. In the SherLOK project, we will try to use hair to learn more about the perpetrator of a crime. It might even be possible to compile an offender’s profile using that one single hair.
Smoker or non-smoker?
A profile is made up of a number of substances that offer a clue about people’s lifestyles. These substances may offer information about nutrition, addictions, habits and activities. We refer to substances that offer these kinds of clues as ‘markers’. Nicotine is a good example of a marker. This substance tells us whether the person to whom the hair belonged is a smoker or not.
One major advantage of hair is that it offers a time indication. Hair grows about 1 centimetre a month. This means you should be able to tell what a person has been up to by analysing their hair. For example, they may have given up smoking recently.
Statistical data show that about 30% of Dutch people are smokers. The more markers we can find, the better we can build up the profile associated with the hair. If we were to find a total of 20 markers with a prevalence of 50%, we would be able to create a profile that matches 1 in 1,000,000 people. This would be of immense value in forensic investigation.
For the SherLOK project, we have teamed up with the Netherlands Forensic Institute, Co van Ledden Hulsebosch Center, Maastricht University, the National Forensic Investigation Team of the Dutch police and KU Leuven. All these partners contribute crucial knowledge of hair or the field of forensics.
Avans students are currently developing measuring methods for different markers. We are also looking for new markers, using modern metabolomics concepts. Metabolomics is the science that studies markers that remain in cells after metabolism. Also contributing to the project are students of the Master's in Forensic Science offered by the University of Amsterdam. Their literature reviews help answer questions that come up in this project, such as the length of time a profile is still identifiable after a person’s death.