Law-enforcement technologyAdvanced technologies shed more light on the killing of Trayvon Martin

Published 5 April 2012

Since only two people know what happened in the confrontation between George Zimmerman and Trayvon Martin, and since one of them is dead, investigators must rely on circumstantial evidence — and on advanced technology; two such technologies — voice biometrics and redigitized imaging — help shed more light on the fateful February night

Controversy continues to build in the Florida killing of an unarmed African-American tennager by a neighborhood watch security officer, and the manner in which the Sanford police has handled the case.  George Zimmerman, the watch volunteer, maintains that he fired in self-defense.

The conduct of the Sanford police has already led to the temporary suspension of the Sanford police chief. The governor of Florida appointed Angela Corey, who has a reputation as a tough, no-nonsense prosecutor, as a special prosecutor to examine the case, and the U.S. Justice Department has opened its own investigation of the case.

Since Zimmerman killed the only other witnesses to the incident, Zimmerman himself, and nearby residents of the gated community who heard cries for help. Those who heard the shouting were divided in whether they believed the calls for help were the voice of Zimmerman or of Martin. There is also a 911 call from a woman in the gated community which was placed early enough for panicked cries and a gunshot to be heard on the tape of the call.

When police officers arrived at the scene — within four or five minutes after Zimmerman called 911 to report that he saw someone who “looked suspicious” —  they found Martin already dead, and reported Zimmerman with a bloody nose and bleeding lacerations on the back of his head. He told officers that when he saw Martin, he followed him on foot, but lost him, and when he returned to his vehicle, Martin attacked him from behind, and a struggle ensued, during which, Zimmerman says, Martin attempted to take Zimmerman’s handgun.

Police arriving at the scene made two emergency medical calls, then after examining Zimmerman, cancelled one of those medical calls. They found Zimmerman injured, but he did not require emergency medical services.

The Orlando Sentinel contacted Tom Owen of Owen Forensics and chair emeritus of the American Board of Recorded Evidence to review the 911 call to determine whose voice was calling for help.

Owen used software called Easy Voice Biometrics, and results of the testing indicated that there was only a 48 percent probability that the voice was Zimmerman’s. Owen added that he would expect a returned probability of better than 90 percent for a positive identification. He was unable to run the test on Martin’s voice because there was no sample available.

The Sentinel also contacted a second voice identification expert, Ed Primeau. who confirmed Owen’s