Authorities filed new charges Wednesday in the four-year-old killing of Metra Police Officer Thomas Cook.
Cook was killed in September 2006 while sitting in his squad car outside the 147th street Metra Station in suburban Harvey when someone shot him in the head and stole his service revolver.
Cook County State's Attorney Anita Alvarez and Chief Tim McCarthy of South suburban Major Crimes Task Force said at a press conference Wednesday the man who shot him is 23-year-old Jemetric Nicholson of Harvey.
Alvarez said Nicholson and an accomplice allegedly shot the officer in order to steal his gun. The alleged accomplice, Jonathon Lloyd, 22, has agreed to testify against Nicholson, Alvarez said.
*Editor's note: portions of this story were changed from the original version.