WASHINGTON — The Justice Department plans to open an investigation into the practices of the Ferguson Police Department following an officer’s shooting last month of an unarmed black man in the Missouri town, a person briefed on the matter said Wednesday night.

The person said the investigation could be announced as early as Thursday. Missouri officials were notified Wednesday of the investigation.

The investigation will look at the practices of the police department, including patterns of stops, arrests and use-of-force, as well as the training the officers receive, the person said.

The investigation is separate from an ongoing civil rights investigation the Justice Department is conducting into the shooting of 18-year-old Michael Brown by Officer Darren Wilson on Aug. 9. A local grand jury is also investigating the shooting, which set off nearly two weeks of unrest in the St. Louis suburb and became a flashpoint in the national discussion of police treatment of minorities across the country. Attorney General Eric Holder two weeks ago visited Ferguson, where he sought to reassure residents about the Justice Department investigation and shared personal experiences of having been mistreated by police.

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

Police have said a scuffle broke out after Wilson, who is white, told Brown and a friend to move out of the street and onto a sidewalk. Police say Wilson was pushed into his squad car and physically assaulted. Some witnesses have reported seeing Brown’s arms up in the air before the shooting, an apparent sign of surrender. An autopsy paid for by Brown’s family concluded that he was shot six times, twice in the head.

Ferguson Police Chief Tom Jackson did not immediately return a call seeking comment.

The Justice Department’s civil rights division routinely investigates individual police departments when there are allegations of systemic abuse or other problems. The department, for instance, issued a scathing report in April that faulted Albuquerque, New Mexico, police for a pattern of excessive force and called for the police to overhaul its internal affairs unit and change policies on deadly encounters.

Many of the investigations end with a federal mandate to make significant changes to policies and practices.