Gleason Bennett Williams murdered five-year-old Shannon Morrissette in 1992. (CBC)

The family of a hearing-impaired Calgary girl who was murdered in 1992 is relieved her killer is dead.

Gleason Williams, 54, strangled five-year old Shannon Morrissette and slit her throat in his southeast Calgary basement apartment.

Police found the girl's body inside a duffle bag in a dumpster. Lab tests were unable to show whether she had been sexually assaulted.

Williams, a native of Prince Edward Island, was found dead in his cell at the Dorchester Institute in New Brunswick on Thursday. The Correctional Service of Canada said Friday the death was an apparent suicide.

Earlier this month, Williams appeared before the National Parole Board to ask for escorted day passes. Parole board officials said he posed a risk to reoffend and his request was denied.

The dead girl's mother, Janet Morrissette, said she was relieved to hear of Williams' death.

"I'm just happy about it … two weeks ago I was worried that he'd be out and I'd be alive to see him free. Now I can live a little bit peacefully."

Shannon Morrissette was hearing impaired and communicated using sign language. (CBC)

Morrissette and other relatives travelled to New Brunswick for the parole board hearing.

"I've seen my sister suffer through the years so badly and in so many ways," said Claudette Kennedy, Morrissette's sister. "Words can't even explain her pain and stuff. I just hope it's some kind of closure for her ... even if it's just a little bit of peace or a little bit of closure for her. I know it will never bring Shannon back."

Dorchester Institute's assistant warden Brenda Hastie said Williams was found during a routine check.

"We found Mr. Williams unresponsive in his cell. Action was taken to, you know, do CPR, take care of him, [but] he was pronounced dead."

The Correctional Service of Canada will review the circumstances surrounding the death.