Updated

District of Columbia officials are proposing additional training requirements for licensed security guards in the city, in part to help them respond to active-shooter situations.

Mayor Muriel Bowser said Thursday the new regulations were prompted in part by two cases in which men died in the custody of security guards. Two former guards at MedStar Washington Hospital Center have pleaded not guilty to involuntary manslaughter in the death of a patient last year. Also last year, a special education teacher died after being taken into custody by security guards at an apartment building.

Bowser and Police Chief Cathy Lanier say the city's 17,000 security guards play a crucial role in public safety and the new training will allow them to do their jobs better.