The mother of a man who was shot and killed by an off-duty police officer is suing the city and the officer, alleging a code of silence among Chicago Police officers stifled attempts to fully investigate the shooting.

Flora Suttle filed the suit in U.S. District Court Thursday on behalf of Derrick Suttle.

On Feb. 11, 2012, the Chicago Police officer was at home with his wife in the 7900 block of South Chappel Avenue when he heard a crashing sound, police News Affairs Officer John Mirabelli said in February 2012.

The officer discovered two men trying to break into his garage by ramming a van into it. When confronted by the officer, Suttle allegedly attempted to run over the officer and his wife. In fear of his and his wife’s safety, the officer shot and killed Suttle, authorities said at the time.

Suttle’s death was ruled a homicide by the Cook County Medical Examiner’s office.

The suit alleges that in the course of confrontation, the officer used unreasonable force and shot Suttle without cause or justification.

It further claims the City of Chicago failed to effectively investigate the shooting or impose any discipline on the officer.

“The policy, practice, and custom of a police code of silence results in police officers refusing to report instances of police misconduct of which they are aware, despite their obligation under police regulations to do so,” the suit states.

The eight-count suit charges the city and Bond with Fourth Amendment violations, wrongful death, a survival claim, family expenses, intentional infliction of emotional distress, a tort immunity claim, a claim of respondeat superior and one claim of municipal liability.

A spokesperson for the city’s Department of Law was not immediately available for comment.

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