Fingerprinting Mummified Remains

Postmortem fingerprint collection is a routine part of many forensic death investigations. Although the production of postmortem prints is usually straight forward, several obstacles and scenarios can make the collection difficult. A common challenge occurs when finger pads are mummified. Several current techniques allow for softening and rehydration of mummified finger pads; however, despite the employment of such techniques, the production of adequate postmortem fingerprints can remain difficult.

The Pima County Office of the Medical Examiner has earned national recognition for breakthrough work with fingerprinting unidentified bodies of people, including border crossers, who have died in the desert.

In arid conditions such as Southern Arizona’s desert, it doesn't take long to run out of water. This, as well as sickness, injuries and other accidents, can lead to fatalities and the dehydration process doesn’t stop after death. Many of the bodies brought to the PCOME’s well lit, tiled hallways have begun to mummify.

When nobody knows who the person was, mummification makes identification an even greater challenge.

It's possible to rehydrate the tissue using sodium hydroxide. The process can take up to 72 hours and requires a mixture of attention and patience.

If printing is attempted too soon, the prints are still distorted — but waiting too long can mean permanently losing the fingerprints.

“The risk again is always you can dissolve the tissue if your solution's the wrong concentration or you leave the tissue in the solution for too long and that kind of thing,” Hess said. “So we have a fairly rigid process.”

It was a process that Hernandez began helping to develop after he started working at the PCOME in 2000.

This article was an excerpt from a full article by the Tucson Sentinel January 2014, read the full article HERE

To hear the full story with Gene Hernandez with Pima County Arizona on how this process works listen to this episode.