Crime scene age prediction – new methods of analysis for bloodstains

Interdisciplinary teams at King’s have been working on research to provide new methods of analysis for blood stains at forensic crime scenes. New techniques could help forensic experts to  more accurately predict the age of victims and suspects  as well as how long it has been since a blood stain was deposited.

Bodily fluids are among the most important biological evidence recovered from crime scenes, but predicting the age of a sample donor is challenging. 

Researchers from  King’s Forensics  have now been able to accurately predict the age of sample donors to within four years (on average) with a technique that uses a form of artificial intelligence or ‘machine learning’ to analyse a specific set of 16 key biomarkers.

They also found their model has the potential to perform well in diseased samples of blood and saliva. With more data, the model could be retrained to apply to other tissues, such as sperm or urine.

One of the researchers,  Dr David Ballard , said: ‘This is the first study to test next generation sequencing and machine learning technologies together to estimate age from blood and saliva samples. These findings could provide a basis for combined analysis techniques that would be of substantial value in forensic investigations in the future. 

Scientists are also working on a technique which uses ultraviolet light of a certain wavelength to determine the time from the creation of a bloodstain. It does this by looking at the fluorescence present in the blood, which fades over time. This allows more accurate estimations of when the bloodstain was deposited from hours to days.

Uncertainty over the time that a blood deposit was made has led to the rejection of forensically valuable evidence in the past. The new method could help police gather more accurate evidence such as information about the time a crime occurred or to discount irrelevant blood at crime scenes.

Working alongside colleagues from the Department of Physics, Dr Nunzianda Frascione from King’s Forensics said: ‘Even small bloodstains can be dated and used by police to determine when the crime was committed. Blood fluoresces naturally under ultra-violet light, and so this technique could be highly accurate and the next stage now is to move to further trials in the field.’

Interested in studying Forensic Science? Visit the King’s College London website.