Investigators, scientists team up to find better way to identify Jane, John Does

Dutch forensic investigators and scientists have teamed up to find better and more efficient ways to identify unknown deceased persons in cold cases. They found ways to divide a single tooth or nail so that four or five scientific studies could happen on them simultaneously. With the nails, 100 percent of the studies led to useful information; with the teeth, it was 76 percent, the Police and Science Research Program announced.

Teeth and nails can say a lot about a person, but the police don’t always have a lot to work with when they find parts of a skeleton in the woods or a jawbone washed ashore, for example. With this new method, even a tiny bit can go a long way in helping identify a person.

For example, DNA can be extracted from a tooth to determine the person’s gender and identity. An anthropologist can learn a person’s approximate age. Toxicologists can extract information from teeth about possible medication and drug use. Carbon dating can determine a person’s date of birth, and isotope research can indicate in what region a person lived. The researchers figured out how to divide one tooth so that all five studies could happen at the same time.

Nails can also say a lot about a person’s recent path. The scientists divided one nail into four for toxicology, carbon dating, isotope, and DNA research.

“That makes a great combination,” said Rogier van der Hulst, a forensic toxicologist at the Netherlands Forensic Institute (NFI) and project leader. “All of these results together help to draw up a good profile of the unknown deceased person. If all the tests pass, you have the year of birth, year of death, age, gender, the region where the person grew up, the region where the person died, and any medicines and drugs they used.” That can go a long way in helping the police put the puzzle of a person’s identity together.

The scientists tested their method on the teeth and nails of seven people who donated their bodies to science. For the nails, all studies provided useful information. The teeth got a 76 percent score, mostly because people who donate their bodies to science tend to be older. “Most of the teeth were in a very poor condition.” Van der Hulst expects better results when this method is applied in practice. “Missing persons are often younger and have better teeth. So I expect an even higher chance of success in real cases.”

The scientists involved in this project were from the NFI, the University of Groningen, Amsterdam UMC, and VU University Amsterdam.