CALGARY -- Randolph Westman pleaded guilty to manslaughter Monday for his role in the death of his roommate in the mid-1990s.

The 58-year-old was charged with second-degree murder and committing an indignity to a dead body in 2018 following a decades-long investigation into the disappearance of 22-year-old Daniel Boysis.

Boysis, who lived in the northeast Calgary neighbourhood of Falconridge, was killed in late 1996 but was not reported missing for a significant time afterward as he had fallen out of contact with his family.

Investigators suspected Boysis, who was also known as Daniel Morgan Turner, had been murdered but his remains have never been located.

A review of the case in the summer of 2016 led police to identify Westman as a suspect after new information surfaced. Westman was Boysis's roommate in 1996. Investigators determined Westman fatally attacked Boysis and disposed of the body.

Westman's attorney Darren Mahoney confirmed to CTV News Monday that his client entered a guilty plea to the lesser charge of manslaughter.

A date for sentencing has not been confirmed.