Using Impression Evidence to get a Conviction

Impression evidence can be an important part of any criminal investigation. This type of evidence is created anytime one object or material that can be manipulated with force is pressed against another object, allowing the objects to transfer and retain characteristics from one another. Impression evidence is used by investigators to examine and compare the impressions and characteristics of a suspect, or characteristics of something a suspect owns or was in possession of at the time of the crime, in an attempt to identify common distinctive details in order to get a match; thereby linking a suspect to the crime. There has always been some speculation as to the onus that should be put on impression evidence to get a conviction when it is the primary evidence against. The question then remains, is impression evidence, alone,—particularly palm prints, lip prints, and bite marks—sufficient enough evidence to sustain a conviction?

There have been several cases involving the three said types of impression evidence (as the only real evidence against) over the years that have been overturned. Ray Krone, once branded the “snaggletooth killer,” was released from the Arizona State Prison in 2002 after DNA cleared him of the killing of Phoenix cocktail waitress, Kim Ancona, back in 1991. A bite mark on the victim’s breast (and the testimony of Dr. Raymond Rawson, the State’s dental expert) was basically the only evidence that convicted Krone of the murder. But later DNA analysis found that the true identity of the killer was a man already incarcerated on another unrelated offense.

In 1997 Lavelle L. Davis was convicted of shooting to death Patrick Ferguson in Illinois in 1993. The evidence that led to the conviction of Davis centered largely on a lip print recovered from the scene that a forensic examiner testified linked Davis to the scene. Davis finally got an appeal hearing in 2006; and there judge, Timothy Q. Sheldon, reversed the conviction, noting that lip prints were not and had never been an accepted means of identification. Prosecutors dropped all charges against Davis in 2009.

Back in 2004, Brandon Mayfield, an Oregon attorney and Muslim convert, was held as a material witness in the Madrid train bombing of 11 March 2004, “a terrorist attack in which 191 people were killed.” Mayfield was picked up after a latent palm print (attributed to him by FBI senior fingerprint examiner, Terry Green) was lifted off of a bag that was recovered in Madrid containing detonators and explosives. They held Mayfield despite his claims that he had not left the U.S. in almost ten years and did not even own a passport. A few weeks later the FBI retracted the identification and issued an apology to Mayfield. Police now believe that the prints belong to Daoud Ouhnane, who is still a fugitive, and that he was the mastermind and chief coordinator of the attack in Madrid.

These three cases show the importance of not rushing to judgment when it comes to impression evidence, as well as not putting too much onus on this type of evidence without more corroborating physical evidence. There are, unfortunately, many more cases like these to draw from. When it comes to these three types of evidence; there have been no peer-reviewed studies, no systems of classification, and no means of individualization developed. The use and study of impression evidence should not be completely undermined here, however. Investigators still must have an awareness of print transfer basics, as impression evidence has aided in the conviction of many criminals who actually committed the crimes. They also aid in the formulation (or investigator reenactment) of the crime, helping investigators build a better picture of what happened and helping them know where to search next.