Jemetric Nicholson guilty in Metra cop's murder in 2006

MARKHAM, Ill. (WLS) -- A jury has found Jemetric Nicholson guilty of one count of first-degree murder in the shooting death of a Metra police officer in 2006.

Officer Thomas Cook was shot in the back of the head at the Harvey train station after a string of armed robberies.

Defense attorneys argued there was no physical evidence, just the testimony of an alleged accomplice who struck a deal with the state.

In October, the judge declared a mistrial in Nicholson's case because the jury could not agree on a verdict.