The 29-year-old man who gunned down 15 people on the Danforth Sunday night had previously been investigated by Toronto police under the Mental Health Act, CP24 has learned.

A police source told CP24 that in 2010, Faisal Hussain made comments to school officials at Victoria Park Collegiate Institute that led them to contact police.

According to the source, Hussain spoke about being “The Joker” from the Batman movie and talked about “liking death” and “explosions.”

The Mental Health Act allows police to interview a person and make an assessment about whether they pose an immediate threat to themselves or others.

Federal Public Safety Minister Ralph Goodale said earlier Tuesday that Hussain was not on any federal watchlists.

“As far as we’re aware at this stage based on the state of the investigation, which by the way is led by the Toronto Police Service, there is no connection between that individual and national security,” Goodale told reporters Tuesday.

Investigators continue to try and piece together what caused the rampage that left an 18-year-old woman and a 10-year-old girl dead and 13 others injured.

On Monday night, forensic officers were seen at a Thorncliffe Park Drive apartment complex where the suspect, identified by the Special Investigations Unit as 29-year-old Toronto resident Faisal Hussain, lived with his parents.

Hussain’s family released a statement Monday, saying that their son suffered from “severe mental health challenges,” including psychosis and depression.

“We are utterly devastated by the incomprehensible news that our son was responsible for the senseless violence and loss of life that took place on the Danforth,” the family’s statement read.

Acquaintances of Hussain described him as “polite,” “respectful,” and “friendly.”

When asked about potential motives, Toronto Police Chief Mark Saunders said investigators are considering all possibilities.

Homicide Det.-Sgt. Terry Browne, who spoke to reporters on Monday, said police are looking into the suspect's background as part of their investigation.

"I can’t speak to what was in this individual’s mind. We’ll certainly dissect everything,” he said.

Nine people still in hospital

Nine people remain in hospital following the deadly mass shooting on the Danforth on Sunday.

Three patients are receiving treatment at Sunnybrook Hospital, five are at St. Michael’s Hospital, and one patient remains at Michael Garron Hospital.

Six victims are listed in critical condition, one is in stable condition, and two are said to be in “good condition.”

Witnesses say the suspect fired at unsuspecting people on the street as well as people sitting in restaurants.

According to investigators, the incident unfolded “very quickly” and ended in the death of the gunman, who sustained a fatal gunshot wound.

The two victims killed in the attack have been identified as 18-year-old Reese Fallon and 10-year-old Julianna Kozis from Markham. The 13 surviving victims are between the ages from 17 to 59.

Residents of the Greektown neighbourhood where the shooting took place are still reeling from the deadly attack.

A candlelight vigil was held on the Danforth on Monday night and flowers, as well as messages of support, have been placed along the street where the mass shooting occurred.