MILWAUKEE (AP) – A Milwaukee police officer who fatally shot a black man in August, sparking several nights of unrest on the city’s north side, has been arrested on a sexual assault charge in an unrelated case.

Police released a statement Thursday saying Officer Dominique Heaggan-Brown was arrested Wednesday after the Milwaukee County prosecutor filed a criminal complaint. Police say the unidentified victim told police on Aug. 15 that Heaggan-Brown had sexually assaulted him while off duty.

Police say they’ve launched an internal investigation. Heaggan-Brown is suspended and in custody.

The head of the Milwaukee police union didn’t immediately respond to a phone message seeking comment from The Associated Press.

Heaggan-Brown fatally shot 23-year-old Sylville Smith on Aug. 13 after a chase. Police say Smith was holding a gun when he was shot.