The Royal Newfoundland Constabulary is investigating the sudden death of an inmate at Her Majesty's Penitentiary in St. John's early Saturday morning.
Emergency crews arrived just after midnight and transported a 31-year-old man to hospital where he was pronounced dead on arrival.
The constabulary's major crimes unit and a forensics team are at the scene and continuing their investigation.
An autopsy is expected to be performed on Sunday.
Police are not releasing any further details.
A police spokesman said an update on the case will be released Monday.