Gabriel E. Novick, M.D. Ph.D., Patricia P. Hamby, M.S., Sandra M. Sovinski, B.S. and Mohammed A Tahir, Ph.D.
Indianapolis-Marion County Forensic Services Agency, 40 South Alabama Street, Indianapolis, Indiana 46204

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DNA typing represents the most discriminating tool available for forensic identification of body fluid and tissues. The standard procedure entails the comparison of the evidence with blood standards obtained from the victim and suspect or suspects. In cases where the suspect is already in custody at the time of the collection of the blood standard, law enforcement personnel verify the identity of the inmate, collect the blood, and submit the sample to the DNA lab.

We report a case in which overlooking one element in this sequence could have dramatically changed the outcome of the case.

In February of 1994, a 42 year-old woman was approached by a young man who started striking her about the head and body. The man dragged her to a nearby alley where he raped and sodomized her repeatedly.

The victim immediately reported the assault and described the attacker. The suspect was arrested based on the following evidence: (1) the assault occurred inside a car owned by a close relative of the suspect; (2) the victim identified the suspect from a photo array; (3) the victim spotted, identified and reported the suspect to the police while walking on the street with her husband; (4) and the suspect was wearing the same shoes described by the victim as the ones worn by the assailant.

RFLP analysis was conducted in our laboratory and the results excluded the suspect. The other evidence was so strong that the prosecution recommended that the analysis be repeated after obtaining a new blood standard from the suspect. This time, surprisingly, the suspect was included with probabilities greater than 1 in 200 million for all databases.

Further investigation revealed that during the collection of the suspect’s blood standard for the first analysis, he switched his identification wristband with another inmate, whose blood was drawn instead. This resulted in the exclusion obtained in the first analysis.

Since this incident, security measures have focused on unquestionably identifying the inmates at the time of collection of blood standards. Current policies include the use of a wrist band with a photograph of the inmate, a thumbprint card with a writing sample and a photo ID with a brief history.