Washington police are investigating the death of a 27-year-old man found handcuffed in the custody of special officers, authorities said.
The man, Alonzo Smith, was discovered by officers on Sunday unconscious and not breathing at a residential building, the Metropolitan Police Department said in a statement late on Tuesday.
The police officers had responded to a report of an assault. Smith was in the custody of special police officers when they arrived, the statement said.
Smith was transported to a hospital, where he died. In the U.S. capital, special police could be security guards, campus police, hospital guards and the like, a police spokeswoman said.
The issue of police brutality has generated protests and national debate since the deaths of unarmed black men in Missouri, New York and elsewhere at the hands of officers in 2014.
(Reporting by Ian Simpson)