An inmate at Her Majesty's Penitentiary in St. John's is dead after being taken to hospital earlier this week.
In an emailed statement to CBC News, the Department of Justice and Public Safety said the man was found unresponsive in his cell on Thursday and was rushed to hospital, where he died Sunday.
The department did not specify the cause of death.
"A thorough review will examine all the circumstances surrounding the death, including staff response and the appropriateness of related policies and procedures," the statement read.
The inmate is at least the sixth to die in a Newfoundland and Labrador jail in just over four years.
Jonathan Henoche, 33, died in the penitentiary on Nov. 6, 2019 while awaiting trial on first-degree murder charges.
Henoche's death was ruled a homicide a month later and 10 guards were arrested and charged in connection with his death. The charges were dropped against one of the guards.
In 2018, an independent report was completed by retired Royal Newfoundland Constabulary superintendent Marlene Jesso after four people in provincial jails died within a 10-month span.
The four inmates — Doug Neary, Skye Martin, Samantha Piercey and Christopher Sutton — all died alone in their cells between Aug. 31, 2017 and June 30, 2018.
The Jesso report's 17 recommendations included building a new jail, creating mental health units in the existing institutions and cutting down on the drug trade inside HMP.