Officers are being investigated by the police watchdog after a 57-year-old man died in custody hours after his arrest in Greater Manchester.
The man was arrested over a reported disturbance in Stockport at about 4.30am on Sunday, but became unwell after arriving at Cheadle Police station, officers said.
Greater Manchester Police (GMP) called medics and the man was taken to hospital where he was pronounced dead at about 6.50am.
The Independent Officer for Police Conduct (IOPC) opened an investigation within an hour.
GMP Chief Superintendent Wayne Miller said: "Earlier this morning we received a report of a disturbance at a property in Stockport.
"Local officers swiftly responded to the incident and arrested a man.
"On arrival at Cheadle Police Station, the man became unwell and he was taken to hospital but he was sadly pronounced dead."
Regional IOPC director Amanda Rowe said "a thorough investigation into all the circumstances" will be carried out.
