TORONTO — The 28-year-old man who attacked a mosque in a Quebec City suburb in January 2017 spent hours in front of his computer screen reading about mass shooters and scouring the Twitter accounts of right-wing commentators, alt-right figures, conspiracy theorists and President Trump, according to evidence presented at his sentencing hearing this week.

On Monday, prosecutors revealed a 45-page document itemizing the contents of a computer belonging to the shooter, Alexandre Bissonnette, who pleaded guilty last month to six counts of first-degree murder and six counts of attempted murder in an attack that sent shock waves through Canada, a country unaccustomed to mass shootings. Six people were killed and 19 were injured in the attack.

Parts of the document, according to the Montreal Gazette, show that Bissonnette — who has appeared in a selfie sporting a red Make America Great Again cap — searched for President Trump a total of 819 times across Twitter, Google, YouTube and Facebook. Bissonnette paid particular attention to the president’s Twitter feed, which he searched for 417 times.

Bissonnette also appears to have obsessively visited the Twitter accounts of Tucker Carlson and Laura Ingraham, Fox News personalities; David Duke, the former leader of the Ku Klux Klan; Alex Jones of Infowars; conspiracy theorist Mike Cernovich; Richard Spencer, the white nationalist; and senior White House adviser Kellyanne Conway. Bissonnette checked in on the Twitter account of Ben Shapiro, editor in chief of the conservative news site the Daily Wire, 93 times in the month leading up to the shooting.

The court heard that Bissonnette confessed to a social worker several months after the attack that he idolized mass shooters and wished that his own attack had been more deadly. The contents of his laptop reveal that he spent hours looking up mass killers like Dylann Roof, the white supremacist who killed nine churchgoers at the Emanuel African Methodist Episcopal Church in Charleston, S.C., and Marc Lépine, a misogynist who massacred 14 women at Montreal's Polytechnique engineering school in 1989, according to CTVNews.ca.

Bissonnette opened fire on roughly 50 worshipers who had just completed their evening prayers at the Islamic Cultural Center in the Quebec City suburb of Sainte-Foy on Jan. 29, 2017. In the days after the attack, those who knew him said that he frequently espoused anti-immigrant sentiments.

In a video of his police interrogation shown to the court last week, Bissonnette is heard telling officers that his three-minute-long attack was set off by Prime Minister Justin Trudeau’s message of welcome to refugees in the wake of President Trump’s entry ban, which was issued two days before the mosque attack. As chaos spread across airports around the world, Trudeau tweeted: “To those fleeing persecution, terror & war, Canadians will welcome you, regardless of your faith. Diversity is our strength #WelcometoCanada.”

“I was watching TV, and I learned that the Canadian government was going to take more refugees, you know, who couldn’t go to the United States, and they were coming here,” Bissonnette told police in the video. “I saw that and I, like, lost my mind. It was then that I decided it was time to go.”

He is also heard telling police that he believed his family was at risk of a terrorist attack and that he began to start thinking about taking matters into his own hands after an Islamic State-inspired terrorist plowed his vehicle into people celebrating Bastille Day in Nice, France, in 2016, killing 86 people.

Bissonnette faces life in prison, but a judge will decide whether he should be eligible for parole.

Read more