The man was found unresponsive when officers checked on him
The Independent Police Complaints Commission (IPCC) has launched an investigation into the death of a man in police custody in Bath.
The 39-year-old man was arrested in Wells Road on Tuesday evening and taken to Bath central police station.
An IPCC spokesman would not confirm why he had been arrested but said it was for "his own safety".
During a check, officers found the man unresponsive. He was taken to the Royal United Hospital but pronounced dead.
The IPCC said it would independently investigate the death and a post-mortem examination will be held on Christmas Eve.
A spokesman for the IPCC said it would not be releasing details of the man's identity until the new year.