Barry Manion was found dead in his jail cell last Friday. (CBC)

The lawyer for a recently convicted child killer who was found dead in his cell last week is raising questions over the level of supervision of his client at an Ontario prison.

Provincial police confirmed Barry Manion died early Friday morning at the Monteith Correctional Complex near Timmins, Ont.

An autopsy is scheduled to be performed on Monday, but media reports said the 61-year-old former London, Ont., resident was found hanged.

Just 48 hours before he was found dead, Manion received a life sentence for second-degree murder with no possibility of parole for 10 years in Katherine May Wilson's 1970 disappearance in Kirkland Lake.

Aaron Harnett, who represented Manion in court, told CBC News on Monday he was concerned Manion may have been ignored by jail staff after he started serving his life sentence.

He said his client should have been placed under increased surveillance, in light of the strong emotional content of victim impact statements from Wilson's sisters.

"It wouldn't have been a big stretch to wonder whether or not, in those circumstances, he might have harmed himself," Harnett said.

Provincial police and the province's Ministry of Corrections have declined to comment on Manion's death because it is under investigation.

A coroner's inquest, which is normal after an inmate dies, will follow Monday's autopsy.

'I wanted to see him suffer in jail': victim's mother

Aline Wilson, Katherine Wilson's mother, told CBC News she feels bad for Manion's family, but wasn't surprised to hear the news.

"I wasn't too happy it happened," she said. "I wanted to see him suffer in jail for at least 10 years."

Manion was arrested in January and initially charged with first-degree murder, abduction and forcible confinement.

He resided in Kirkland Lake when Wilson went missing on Oct. 10, 1970. He is a distant cousin of the missing girl, her family has said.

Manion, who had co-operated with police since his arrest, told investigators he offered the girl a ride home, but instead took her to a wooded area because he wanted to have sex with her.

The girl's body has never been found.