No details have been given about the identity of the man, who died on Saturday afternoon at a property in Bath Street in town.
Officers say that there are no suspicious circumstances, but that an investigation has been launched.
In a short statement released this morning, the police said: “Police are investigating the sudden death of a 20-year-old man having been called at 4pm on Saturday December 13th to an address in Bath Street, St Helier.
“There are no suspicious circumstances surrounding this death and a file is now being prepared on behalf of the Viscount.”
