Cook County Judge Nicholas Ford sentenced 40-year-old Lamar Cooper on Tuesday. The sentence carries no possibility of parole. Jurors found Cooper guilty of first-degree murder in January in the slaying of Officer Nathaniel Taylor Jr. Cooper's defense attorney had argued he was acting in self-defense and didn't realize Taylor was a police officer.
Prosecutors say Taylor identified himself as a police officer and had a warrant to search Cooper's South Side home for suspected drugs and weapons.
Cooper previously has served prison time for attempted murder of a police officer.