WASHINGTON (AP) — The Justice Department launched a broad investigation Thursday into the police department in Ferguson, Missouri, following the shooting last month of an unarmed black 18-year-old by a white police officer.

The investigation, which is separate from an existing federal probe into the Aug. 9 shooting of Michel Brown, will look for patterns of discrimination within the predominantly white department and focus on how officers use force, search and arrest suspects, and treat inmates at the city jail. The police department said it welcomed the investigation.