A man who was "restrained" by Devon and Cornwall Police before being taken into custody has died, the police watchdog confirmed.
Thomas Orchard was arrested by the force in Exeter city centre on October 3 on suspicion of a public order offence.
But he was later taken to the Royal Devon and Exeter Hospital when officers became concerned that the 32-year-old was not responding to them while in his cell.
An Independent Police Complaints Commission (IPCC) spokesman said its investigation would aim to discover whether or not Mr Orchard's head injuries were sustained during his arrest. He died in hospital at 6pm on Wednesday, the IPCC said.