(CHICAGO) A Chicago gang leader of the Maniac Latin Disciples was sentenced to life in prison in connection with a 2010 fatal shooting.

Andrew Ruiz, 34, and co-defendant Edwin Carrasquillo, 24, were previously convicted for the first-degree murder of Adrian Gates, 24, according to a statement from the Cook County state’s attorney’s office.

Ruiz–already serving a 99-year sentence from an previous murder conviction–was sentenced to life in prison by Judge Domenica Stephenson on Thursday. Carrasquillo is still awaiting sentencing.

According to prosecutors, on the evening of June 15, 2010, cousins Ruiz and Carrasquillo were driving a white minivan in the 3000 block of West Grand when they pulled up behind a parked car occupied by Gates and his girlfriend.

When Gates got out of the vehicle and began crossing the street, Carrasquillo walked up from behind and shot Gates in the back of the head, prosecutors said.

Carrasquillo then got back in the van and Ruiz drove them away from the scene. Chicago Police officers on patrol in the area later tracked down Ruiz and Carrasquillo about three miles from the location of the shooting.

There were multiple eye-witnesses to the shooting, and the murder weapon was recovered near the I-290 expressway after additional witnesses told authorities they saw someone throw a gun out of the passenger window of a van that matched the description of the vehicle used in the attack, the state’s attorney’s office said.

Ruiz was convicted and sentenced to 99 years for a fatal drive-by shooting on Halloween in 2009 that killed 23-year-old Manuel Roman and seriously injured another man.