The man accused of ploughing a rental van into pedestrians in Toronto has been charged with 10 counts of first-degree murder as investigators gather clues toward a possible motive.

Alek Minassian, 25, entered a Toronto courtroom on Tuesday morning local time and looked down as prosecutors charged him in the death of 10 pedestrians and the injury of 15 others.

While the rampage had the hallmarks of Islamic State-inspired vehicle attacks, Canadian authorities resisted blaming the incident on terrorism.

In a possible clue to a motive, Minassian apparently praised another mass killer in a post on what is believed to be his Facebook page.

HuffPost Canada has confirmed the now-deleted Facebook account belonging to Minassian referenced an “Incel Rebellion” in a post on the same day as the attack saying it had “already begun”.

The post read. “The Incel Rebellion has already begun! We will overthrow all the Chads and Stacys! All hail the Supreme Gentleman Elliot Rodger!”

The term “incel” is short for involuntarily celibate, and originated on Reddit with a large group of mostly young men who were angry about their lack of sexual activity and partially blamed women, according to The Globe and Mail.

Chads and Stacys are reportedly dismissive slang for men and women with more robust sex lives.

“All hail the Supreme Gentleman Elliot Rodger!” was an apparent reference to a deadly 2014 mass murder near the University of California, Santa Barbara.

Rodger killed six people and injured 14 others in a stabbing, shooting and vehicle-ramming attack before dying of a self-inflicted gunshot wound.

Investigators believe Rodger was motivated by a personal grievance influenced by extremist anti-female views.

Police spokesman Detective Sergeant Graham Gibson told a media conference Minassian’s victims were “predominantly” women, but said he had no indication yet that women were specifically targeted.

Sergeant Gibson said investigators were trying to fill in the gaps of Minassian’s movements earlier on the day of the attack and a mobile phone was seized from the suspect at the scene.

He said it was premature to comment on any potential motive and declined to comment on Minassian’s mental health.

It was earlier revealed that Minassian served briefly in the Canadian armed forces before being discharged at his own request after just three months.

Minassian was remembered as ‘absolutely harmless’. Photo: Facebook

The suspect’s two-story red-brick home in a suburb north of Toronto was a crime scene Tuesday, taped off and surrounded by police vehicles. Officers went in and out of the house.

The officer who apprehended Minassian was praised for making a peaceful arrest even as the suspect shouted “kill me” and claimed to have a gun.

Canadians mourned as the victims began to be identified on Tuesday.

The Canadian Broadcasting Corp identified one of the victims as Anne Marie D’Amico, an employee of asset manager Invesco Canada.

“I can now confirm that unfortunately one of our employees has succumbed to her injuries. Out of respect for her and her family, we will not be providing any further comments,” Invesco Canada president Peter Intraligi said in a statement.

Ms D’Amico is the fist victim to be identified.

Two South Korean citizens and a Jordanian national are also thought to be among the victims.

The attack shook the usually peaceful streets of Toronto, a multicultural city with a population of 2.8 million. The city recorded 61 murders last year.

Mr Trudeau called on all Canadians to stand united with Toronto as flowers and scrawled messages in multiple languages piled up at a makeshift memorial in Toronto’s north end, an ethnically diverse neighbourhood of towering office buildings, shops, restaurants and homes.

“We cannot as Canadians choose to live in fear every single day as we go about our daily business,” Trudeau said outside parliament in Ottawa. “We need to focus on doing what we can and we must to keep Canadians safe while we stay true to the freedoms and values that we all as Canadians hold dear.”

The Prime Minister said that, while it would take time before the motives of the attacker were understood, the incident had not changed the country’s threat level or security preparations for a G7 summit in Quebec in June.

The Canadian flag was lowered to half-mast at parliament and at Toronto city hall.

Downtown Toronto’s iconic CN Tower, which is normally lit up in the evening, went dark on Monday evening.

-with agencies