Bernard Williams, 18, of Chicago, has been charged with first degree murder and armed robbery, according to the Cook County State's Attorney's Office. He is expected in court on Thursday.
Blake was off-duty last month when he was shot and killed in his SUV, which was parked in an alley in the 2900-block of West Seipp Street. His wallet and gun were found in the vehicle and the windows were still rolled up, leading investigators to believe Blake knew his killer.
Blake was a 15-year veteran of the Chicago Police Department and a SWAT officer. He was a highly decorated officer who won 84 departmental awards during his career on the force, police said. He played running back on the department's Chicago Enforcers football squad.
His death stunned fellow officers.
"It was a shock to find out what happened. We're a close knit group of people. And we're still absorbing it," said Lt. Mark Marianovich, Chicago police officer.
"We are just doing our best to help each other in terms of dealing with this situation," said Norell Liboy, Blake's partner.
ABC7 has learned Williams is the brother of a woman who says she was Blake's girlfriend.
Blake is one of six police officers killed this year:
- February 22, 2010: Sgt. Alan Haymaker was killed in a vehicle accident while responding to a burglary call.
- May 19, 2010: Officer Thomas Wortham IV was shot to death during a robbery attempt in Chatham.
- July 7, 2010: Officer Thor Soderberg was shot to death with his own weapon.
- July 18, 2010: Officer Michael Bailey was shot outside his home.
- November 26, 2010 : Officer Michael Flisk was shot to death while processing a burglary scene.