Bringing the Lab to the Crime Scene

A new handheld spectrometer could soon offer police a way to distinguish human blood from animal blood on the spot at a crime scene. The tool would save valuable time and money in determining which samples are relevant to the case without destroying them in the process.

Current analysis methods use biochemical reagents and require a desktop lab instrument, making it impossible to conduct tests in the field. The new technique shines infrared light on the sample and records subtle changes in the spectrum that occur with variations in blood composition. A machine learning algorithm is then used to distinguish human blood from that of ten animal species, including dogs, cats, ferrets, deer and elk.

Spectroscopy-based devices are well-suited for portable applications; however, further testing is required to calibrate the system with increasingly diverse species and widely variable diets. The researchers are collaborating with the New York State Police Crime Laboratory System to test the method in real crime scene settings.