The family of a 19-year-old man fatally shot by a Wisconsin police officer in March filed a federal civil rights lawsuit on Wednesday, accusing the officer of acting unconstitutionally and lying to investigators.

Tony Terrell Robinson Jr. was shot and killed by Madison Police Officer Matt Kenny on March 6, after police said Kenny responded to a report of a possible battery, entered a home where he believed an assault was taking place, and was then allegedly attacked by Robinson in a stairwell. The shooting sparked protests amid claims of excessive use of police force.

The Dane County district attorney in May announced that Kenny would not face criminal charge s, and said the shooting was lawful. A police internal review also cleared Kenny  of wrongdoing.

"At no point during Tony Robinson's encounter with Defendant Kenny did Robinson take any action that would justify the use of deadly force," the lawsuit reads. The suit names Kenny and the city of Madison as defendants, NBC News reports.