A D.C. man died on Thursday morning in a cell block at the Metropolitan Police Department’s Second District headquarters. Police say Marquez Parker, a 44-year-old resident of Northwest D.C., was arrested around 6:45 a.m. Thursday morning — and by 10:30 a.m., when officers “conducted a check” of his cell block, they found him unconscious and not breathing.

MPD’s Internal Affairs Bureau is investigating the death.

According to a statement provided to DCist/WAMU by Metropolitan Police Department spokesperson Paris Lewbel, police called D.C. Fire and EMS, administered Naloxone — a drug used to reverse opioid overdoses — and began CPR on Marquez after finding him unconscious. They also attempted to use a defibrillator on Parker, police said. When Fire and EMS arrived, they pronounced Parker dead.

The cause of Parker’s death is unclear.  The D.C. medical examiner’s office will officially determine his cause and manner of death. Some investigations are more complex than others, and the office tries to arrive at an opinion on cause and manner of death within 90 days of an autopsy.

Parker had been arrested “without incident” by the Capitol Area Regional Fugitive Task Force the morning of his death, according to MPD. The team was executing an arrest warrant for armed kidnapping that occurred in July. Parker allegedly forced his girlfriend into a vehicle at gunpoint in an incident that police say was partially streamed online. His girlfriend was later found safe, the Washington Post reported.