A methadone overdose is believed to be what killed an inmate at the Saskatoon Correctional Centre two years ago, a public inquest into his death heard Monday.

Kevin Umpherville, 22, was found unresponsive in his cell on Dec. 31, 2015. He died about two weeks later on Jan. 15 at Royal University Hospital.

The inquest heard Umpherville was first taken into custody in late December 2015 for charges including assault.

He was readmitted to Saskatoon Correctional Centre on Dec. 30 of that year after treatment at Royal University Hospital for what is believed to have been a methadone overdose, Sgt. Neil Lund of the Saskatoon Police Service told the inquest.

Umpherville was later seen on surveillance video placing a hand over his mouth, likely taking methadone, Lund said. It is believed the methadone was concealed in a deck of cards.

The next morning, Umpherville didn't show up for breakfast, according to Lund. He was found unresponsive in his cell. Staff called an ambulance, which took him to hospital where he was placed on life support.

Umpherville died a day after his family decided to remove life support, the inquest heard.

A staff member at the correctional facility told the inquest Umpherville had admitted to taking methadone, and that he got it from another inmate. The staff member also said there was no indication it was a suicide attempt.

An inquest takes place any time an inmate dies in custody and when a coroner can't say for certain whether a death was preventable or of natural causes.

The inquest is expected to last for three to four days.