Crime Scene Investigator Network Newsletter

Introduction
Controlled studies and efforts by forensic scientists and investigators in the mid-1960s through the 1970s provided a stepping-stone into the recovery of prints from human skin in actual homicide cases. The focus of these efforts seems to have been on determining the best methods to obtain the prints, without considering environmental factors that could possibly impact their successful recovery. In the last 9 years of teaching and 13 years of research on this subject, we have run into the following beliefs and statements:

• It is unlikely that prints may be developed on human skin.
• Fingerprints will have been washed away.
• There are time constraints on the successful recovery of prints from dead bodies.
• The body must be processed at the scene.
• The body must be fresh (not refrigerated).
• Natural skin shedding destroys latent prints left on the skin’s surface.
• Specific surface temperatures of the skin and body are required for the successful recovery of prints.
• Prints can only be recovered from dead bodies.
• Prints have only been recovered from bodies located in Florida and that is because of the use of suntan oil.

Negative attitudes and the lack of definitive guidelines easily equated to a hit-and-miss approach that was usually accompanied by negative results. Processing a body for print evidence can be a long, methodical, labor-intensive task. Even the most experienced investigator may become disillusioned when results are negative. Ongoing research and field applications have proven that, with practice, prints can in fact be successfully recovered.

Background
The authors have gathered and analyzed case histories and published accounts. This effort has led to new areas of research and has expanded the understanding of human skin and the sophisticated level of interaction between skin, latent prints, and the environment. During testing of procedures for the transference or recovery of fingerprint evidence from human skin, it was determined that by raising or lowering, as appropriate, the environmental temperature and relative humidity, print recovery was either increased or decreased. In addition, the surface temperature of the skin could be controlled by mechanical means (such as a small battery-operated fan). Participants in the workshops validated these concepts with their results. This interaction reveals that proportionately balanced relative humidity and temperature, as well as the surface temperature of the skin, are key factors that have been largely overlooked.

Persistence on the part of a few bore fruit in the mid-1970s. The Miami-Dade Police Department in Miami, Florida, had positive results in five cases involving physical assault or homicide. One of them, in 1978, produced the first known identification of prints from human skin that resulted in a first-degree murder conviction. The other four cases included a previously unpublished 1975 assault case that the author worked (an unidentifiable print was obtained from a living victim’s wrist where the suspect had grabbed the victim) and three other previously reported cases. Japan and Canada followed with successful cases in 1981 and 1982.

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