The lone suspect in the shooting at a Quebec City mosque on Sunday night that left six dead is being described as a “loner” and “troll” by people familiar with the suspect’s Facebook posts, Le Soleil, a Quebec City daily, reports.

The suspect, 27-year-old Alexandre Bissonnette, was apprehended by police on Monday morning. Law-enforcement sources told Reuters that this was a “lone wolf” attack. They also confirmed to NBC on Monday afternoon that Bissonnette is the only suspect in the shooting, though police initially apprehended two suspects. The second person apprehended by police is now considered a witness and not a suspect.

Bissonnette studies political science at the University of Laval, a French-language university in Quebec City, according to Le Soleil. “He was practically in all my classes. He’s a loner,” a Laval student told the newspaper. “He doesn’t really have any friends.” Another student, Jean-Michel Allard-Prus, told Le Journal de Quebec, that Bissonnette “had political ideas on the right” and was obviously “pro-Trump.”

Francois Deschamps, a member of Bienvenue aux Réfugiés, an organization that works with refugees and immigrants in Quebec City, told Le Soleil he “jumped” when he saw the photo the newspaper published of Bissonnette on Monday.

Deschamps said that Bissonnette frequently trolled the organization's Facebook page, posting comments attacking women's rights and refugee rights. Deschamps further said that his organization often watches what the "extreme right" are posting on social media.

Alexandre Bisonnette

Foto: Alexandre Bissonnette. source Le Soleil/Facebook

In a Facebook post Monday afternoon, the organization confirmed that Bissonnette was known to activist groups, and that he frequently posted "anti-feminist" and "pro-le Pen" comments on social media.

Marine le Pen, a French politician, is the outspoken leader of the right-wing populist National Front party.

Canadian Prime Minister Justin Trudeau called the shooting a "terrorist attack" in a statement Sunday evening.

"Muslim-Canadians are an important part of our national fabric, and these senseless acts have no place in our communities, cities and country," Trudeau said.

President Donald Trump called Trudeau on Monday to offer condolences and any assistance needed in the aftermath of the shooting. Sean Spicer, Trump's press secretary, condemned the attack in a press conference on Monday afternoon. "We condemn the attack in the strongest possible terms," Spicer said.

"It's a terrible reminder of why we must remain vigilant and why the President is taking steps to be proactive rather than reactive when it comes to our nation's safety and security," the press secretary added, in an apparent reference to the executive order Trump signed on Saturday temporarily banning immigrants from seven majority-Muslim countries.

Portia Crowe contributed to this report.