SUNSET PARK, Brooklyn (PIX11) — A man died in NYPD custody Thursday evening while being held as a robbery suspect in Sunset Park, sparking an investigation, according to authorities.

The man, whose identity had not been released as of early Friday, was found unconscious inside the 72nd Precinct stationhouse on 4th Avenue near 29th Street around 7:35 p.m., police said. Attempts to revive him were unsuccessful, and he was pronounced dead at an area hospital, officials said.

Officers first encountered the man after checking out a 911 report of a dispute involving a knife near 27th Street and 3rd Avenue around 5:55 p.m., authorities said. A 40-year-old man told responding cops that two other men, one of whom had a knife, demanded money from him, then fled, police said.

Investigators soon found two men who fit the description of the suspects, arrested them, and took them back to the precinct stationhouse, officials said. Authorities had not publicly identified either man or specified the charges against them as of early Friday.

At around 6:40 p.m., EMS was called to the stationhouse because one of the men was exhibiting what police described as erratic behavior, but the man refused medical attention, according to officials.

Just under an hour later, officers found the man unconscious, requested that EMS return, and took steps to revive the man, authorities said. Their efforts included performing CPR and administering Narcan, a medication used to treat opioid overdoses, police said. The man was ultimately transported to an area hospital, but could not be saved.

The city medical examiner is working to determine how the man died, and police are also investigating the incident, officials said.