Getting to the root of criminal investigation

Researchers from Michigan State University believe a device used to clean delicate roots for plant research could unearth valuable forensic evidence in criminal investigations.

‘Till now, the science of evidence collection has not been accurate,’ said Jay Siegel, a professor of forensic science and chemistry at MSU. ‘The old-fashioned way – rummaging through soil or vacuumed material by hand with a magnifying glass – takes hours and isn’t efficient. You can sort for days and never see what you want.’

The Trace Evidence Concentrator helps police by meticulously separating evidence – hair, fibres, paint chips – from soil or materials vacuumed from a crime scene.

The device uses hydropneumatic elutriation, which includes a high kinetic energy vortex, air displacement and water-borne low energy separation.

Materials collected by police are placed in a stainless steel container and hundreds of tiny, specifically angled jets of water are shot into the tube, creating a whirlpool.

The system, Siegel said, is based on the idea that material that has less density than the surrounding soil particles will float apart from the dirt. Different filters further separate the remaining evidence, which comes out clean and ready for analysis in minutes rather than hours or days.

Siegel said that trace evidence is an important tool in solving crimes. A tiny fibre or chip of paint can be crucial, yet is neglected because collecting that clue can be so difficult. For example, investigators of the Oklahoma City federal building bombing sifted through vast amounts of rubble.

‘One problem is that the recent interest in DNA evidence is that often investigators are neglecting other kinds of evidence,’ said Siegel. ‘They think if they have DNA, they don’t need to do anything else, and that’s not right.’

The device was born of an unusual marriage of disciplines. Siegel found himself chatting with fellow MSU professor Alvin Smucker, a biophysicist, at a social function. Smucker told him about a device he was working on that would carefully remove soil from the delicate nodules of plant roots. They quickly realised the device would have other uses.

Siegel and Smucker hold the patent for the Trace Evidence Concentrator, which is licensed to and marketed by Peak Industries of Dearborn.

‘Criminals have had a huge advantage,’ Smucker said. ‘Because lab techniques for finding trace evidence are highly laborious, antiquated and controversial.’