WASHINGTON — A 27-year-old man died early Sunday after being held in the custody of special police officers in Southeast D.C., according to the Metropolitan Police Department.

D.C. police say around 4 a.m., officers were called to the area of Good Hope Road Southeast, near 23rd Street Southeast, to investigate a report of an assault at a residential building. When they arrived, D.C. police say Alonzo Smith, of Southeast Washington, was handcuffed and in the custody of special police officers.

Smith was unconscious and not breathing, according to police. Officers began lifesaving efforts, and Smith was taken to a hospital, where he later died.

NBC Washington reports the special officers were working as security guards on the property.

An investigation into Smith’s death is ongoing. At this time, no additional details have been released.