WASHINGTON - A person briefed on the matter says the Justice Department plans to open an investigation into the practices of the police department in Ferguson, Missouri. That's where an unarmed black 18-year-old was shot and killed by a white police officer.

The person said the investigation could be announced as early as Thursday. The

Ferguson riot reveals US racial divide, human rights flaw

official said the investigation will look at the training and practices of the Ferguson department.

The investigation is separate from an ongoing civil rights investigation the Justice Department is conducting into the Aug 9 shooting of Michael Brown. Local authorities are also investigating the shooting.

The person spoke on condition of anonymity because the investigation, first reported by The Washington Post, had not yet been announced.