MEMPHIS, Tenn. (AP) — The fatal shooting of a 15-year-old boy last month by an off-duty police officer is fueling criticism of the Memphis Police Department.

The Sept. 24 death of Justin Thompson is just the latest incident for critics who say there is a long-standing culture of misconduct on the force.

This year, at least 23 Memphis officers and civilian personnel have been charged with crimes, from DUI and drug dealing to human sex trafficking

The shooting was enough to prompt Mayor A C Wharton Jr. to call for an investigation of the force by an outside party, like other major cities have done.

Police Director Toney Armstrong says he staying on the job. He says the actions of a few bad officers have tainted the reputation of the entire force.