A man accused of killing his mother and deliberately setting a house on fire in Toronto was found not criminally responsible of a violent assault on her five years ago, according to documents from the Ontario Review Board.

Joel Vassell is facing one count each of arson and first-degree murder in the death of Yvonne Bachelor-Vassell, who was found inside a northwest Toronto home after a blaze broke out last week.

Months before her death, the Ontario Review Board ruled that her son posed a "significant threat" to public safety and was kept on as a patient of an Ontario mental health facility. He had been under the care of the Ontario Shores Centre for Mental Health Sciences since 2015 when he was found not criminally responsible for an assault on his mother and the attempted murder of his grandmother.

The Ontario Review Board, which oversees cases for all those with an NCR designation, outlined ongoing risk factors after Vassell's most recent hearing in September.

"He rejects his formal diagnosis of schizophrenia, and is ambivalent regarding the beneficial effects of medication," the

board wrote in its ruling in which it ordered Vassell to remain a patient of Ontario Shores forensic program.

"As a result, ... Mr. Vassell is likely to become non-compliant with medication, precipitating a decompensation in his mental state. In that state, Mr. Vassell would experience personal and paranoid beliefs that relate to individuals close to him in his life, and he would be at real risk of acting on those beliefs."

Vassell's last-known lawyer did not respond to request for comment.

Ontario Shores offered condolences to Bachelor-Vassell's family but declined to comment on her son's case, citing privacy concerns.

Yvonne Bachelor-Vassell, 61, was found dead in a burnt-out home in Etobicoke. She was a staff member at Toronto's Centre for Addiction and Mental Health at the time of her death. (Toronto Police Service)

"We acknowledge the treatment of people living with complex mental illness within the forensic mental health system can be difficult for communities to understand," the organization said in a statement.

Toronto police offered few details on the case at the heart of Vassell's most recent charges.

The fire broke out on Dec. 11 in the northwest corner of the city, police said. Bachelor-Vassell's body was found inside the burned-out home, and her son was arrested hours later and charged with arson. Investigators laid the additional charge of first-degree murder against the 24-year-old on Wednesday, they said.

Documents reveal details of mental health problems

Ontario Review Board documents offer more details of Vassell's mental health and legal history.

In November 2014, after seeking help for mental health concerns at local hospitals multiple times, documents show he came at his mother with a knife and punched her multiple times inside their Toronto apartment.

"Once he stopped, he hugged her and told her he loved her," the documents said.

The fatal fire occurred in this home in the area of Triple Crown Avenue and Mare Crescent on Dec. 11. (Jeremy Cohn/CBC)

Weeks later, board records said Vassell broke into his 95-year-old grandmother's home and attacked her with a knife, causing several injuries.

"Mr. Vassell's grandmother subsequently advised that Mr. Vassell had told her, 'I'm here to kill you,"' the board report said. "Mr. Vassell's mother reported that she was shocked to learn that her son had attacked his grandmother, as they had always enjoyed a close relationship."

Vassell was found not criminally responsible in both incidents in June 2015 and immediately detained in the Ontario Shores program.

Over time, his privileges were expanded and he eventually gained permission to live in the community.

CEO of CAMH expresses condolences to family

Documents show he had been living in Richmond Hill, Ont., for roughly a year before the most recent charges.

Bachelor-Vassell, 61, was a staff member at Toronto's Centre for Addiction and Mental Health at the time of her death.

CAMH Chief Executive Officer Dr. Catherine Zahn notified staff of her death in a note distributed last week.

"My thoughts today are with the many staff members who knew and worked with Yvonne and I offer my sincere condolences to her family and friends on behalf of the entire CAMH team," she wrote.

Vassell appeared in court on Wednesday to face the most recent charges and is now being held in custody.

