The French Canadian university student charged with killing six Muslim men during evening prayers at a mosque was known for extreme nationalist views and his support of the French rightist party led by Marine Le Pen.
Alexandre Bissonnette was charged Monday with six counts of first-degree murder and five counts of attempted murder over the shooting rampage at a Quebec City mosque that Canada's prime minister called an act of terrorism against Muslims.
Bissonnette made a brief court appearance and did not enter a plea in the attack staged during evening prayers Sunday.
Wearing a white prisoner jumpsuit, his hands and feet shackled, he stared at the floor and fidgeted, but did not speak.
The 27-year-old suspect, who expressed support for Le Pen and US President Donald Trump on his Facebook page, was known to those who monitor extremist groups in Quebec.
An anthropology and political science major at Laval University in Quebec City, Bissonnette had also expressed support on his Facebook profile for "Generation Nationale," a group whose manifesto includes the rejection of "multiculturalism."
Authorities said Bissonnette was previously unknown to police.
The grandson of a decorated World War II veteran, Bissonnette appears in a Facebook photo as a boy dressed as an army cadet, a military leadership program for Canadian youths.
More than 50 people were at the Quebec Islamic Cultural Centre when the shooting began.
Witnesses described a scene of chaos as worshippers scrambled to find friends and loved ones. In addition to the six dead, 19 people were wounded - all men.
Of the four victims who remained hospitalised, two are still in critical condition, authorities said. The dead ranged in age from 39 to 60.
Prime Minister Justin Trudeau and Quebec Premier Philippe Couillard both characterised the attack as a terrorist act, which came amid strong criticism around the world over Trump's temporary travel ban for people from seven Muslim countries.
Trudeau said in Parliament that the victims were targeted simply because of their religion. Speaking directly to the more than 1 million Muslims who live in Canada, he said, "We are with you."
"Thirty-six million hearts are breaking with yours," Trudeau said.