The medical examiner has told a public inquiry that an elderly Calgary woman died of strangulation at a long-term care facility.

Fong Sue Louis had Alzheimer's and was being treated at the Beverly Centre in Midnapore.

In August of 2008, the 77-year-old was found dead in her wheelchair. She had slipped out of her restraint and was strangled when her seatbelt trapped her by the neck.

On Tuesday, her children attended the inquiry. They are hoping to find answers. "We always wondered what kind of suffering she went through," says her son Soon Louis.

Testifying at the inquiry on Tuesday was Lois' family doctor who said her patient was definitely a candidate for a wheelchair restraint. Dr. Maria Malagon says "It was to stop Louis from wandering about and possibly falling."

Louis' death may have gone undetected for almost two hours.

There are suggestions by other witnesses that Louis may have been struggling to get out of her restraints.

"That's another one of the unknowns. We don't know what transpired between 4 and 5:40, would it have made a difference," says Archie Louis.

The inquiry continues on Wednesday.