Hidden Evidence: Latent Prints on Human Skin

Recommendations

This research indicates that homicide victims should be examined for latent
prints whenever investigators believe that the perpetrator touched the victim.
If possible, bodies should be examined at the crime scene immediately after
the coroner or medical examiner has completed an initial examination and
granted permission. At a minimum, the body should be glue fumed at the scene
to preserve the prints and help prevent contamination or obliteration of
prints when the body is moved.

Ideally, bodies should not be refrigerated prior to examination for latent
prints. The condensation that builds up on refrigerated bodies can have adverse
effects by washing away the prints, reacting with the glue to distort the
prints, or causing the powder to cake, thus losing the prints. Bodies that
have been refrigerated should not be processed until the moisture evaporates,
roughly several minutes, depending on ambient temperature. A control area
of skin least likely to have prints can be tested to ensure that the moisture
has dissipated.

Skin that is warm or near normal body temperature should be glue fumed for
only 5 to 10 seconds. Colder skin should be glue fumed for a maximum of 15
seconds. Regular magnetic powders can then be applied. Any identifiable latent
prints should be photographed first and then lifted using transparent lifting
tape.

Conclusion

For many years, investigators and forensic scientists have tried to retrieve
latent prints from dead bodies, but often the key evidence has been just
out of reach. Frustrated, investigators often gave up after several failed
attempts. This research proves that with practice, it can be done by those
who are willing to try. As it becomes routine for law enforcement to obtain
latent prints from skin, murderers who reach out to harm their victims will
just be putting themselves within easy reach of the long arm of the law.

Endnote

These are commonly used methods for developing latent fingerprints on a variety
of surfaces. For more information, see Chemical Formulas and Processing Guide
for Developing Latent Prints (Washington, DC: Latent Fingerprint Section,
Laboratory Division, FBI, 1994).

Copyright Info