The Eastern Health review says Kerry Murray, 39, was left alone despite being on close surveillance status calling for checks every 15 minutes.
Moreover, a health record initialled by staff indicating those visits were done was contradicted by video footage.
"This documentation is not accurate as video evidence shows no surveillance for 56 minutes prior to the discovery of Mr. Murray unresponsive in his room as well as at other times during the day," it says.
"There is no evidence in documentation that continued clinical assessment was carried out in response to the patient's deteriorating mental status."
The report says Murray was found at about 6:50 p.m. on March 13 hanging by his pyjamas from the door of his room. He had been transferred to the Waterford's forensic unit from Her Majesty's Penitentiary on Feb. 28 after being arrested for breaching a peace bond.
The report was released to The Canadian Press by Murray's mother, Joanne Calhoun.
"He didn't receive the watch and the care he was supposed to at Waterford," she said from Edmonton. "The system failed him."
A spokesperson for Eastern Health, the province's largest health authority, said Thursday it deeply regrets what happened.
"We take critical incidents very seriously and are committed to taking actions toward quality improvement," Zelda Burt said in a written statement.
"We continue to examine our policies and procedures within our Mental Health and Addictions Program, which will include an external review specific to the program's forensic service."
Burt said a consultant for that outside assessment has not yet been chosen.
The internal review recommended external scrutiny "to ensure that care and treatment of patients are consistent with evidence-informed practices."
It found a lack of clarity around how staff are assigned to patients, and confusion about how infrequent "Code Blue" medical emergencies should be handled.
It also calls for clear interpretation of all legislation governing forensic patients admitted under the Prisons Act, and says a court liaison position should be explored.
Eastern Health announced March 26 it had fired three staff and was investigating an "unexpected death" at the Waterford.
"While we can't speak publicly to the specifics of the investigation, we can say that we will not tolerate disregard for established protocols," President and CEO David Diamond said at the time.
The internal review says staff repeatedly reported in the days before Murray's death that he was suicidal.
"Mr. Murray tearful and agitated at 17:45, stated that he was having thoughts of harming himself," says an excerpt dated March 10.
Murray was periodically given Ativan, used to ease anxiety.
On the day he died, Murray was scheduled for court after which he hoped to be released from custody, Calhoun said. He was traumatized from a physical and sexual attack nine years ago by four inmates after he was arrested in Calgary for an attempted bank robbery, she said.
Her son, who had worked as a crane operator, had since tried to rebuild his life and desperately feared landing back in jail, Calhoun said.
The internal report affirms that dread.
"Kerry continues to have periodic flashbacks and nightmares of sexual assault on him in 2006/2007 at a remand centre in Calgary," it says. "He feels anxious when he thinks of it. He cried talking about it."
Murray's lawyer, Bob Buckingham, said in March that his client, a father of two, was arrested for texting someone he had been ordered to stay away from.
On the day Murray died, his case was delayed because court had not received a letter expected from a psychiatrist, says the report.
Calhoun said he was crushed but talked on the phone with her just before his death about getting back to Edmonton.
"You've taken care of me all my life," he told her. "Now it's my turn to take care of you."
Follow @suebailey on Twitter.Suggest a correction