Teen Recounts Grisly Scene at Quebec City Mosque Shooting: 'I Was Scared Out of My Mind'

Six were killed in the Sunday night shooting in Canada.

— -- A teenager who said he left a Quebec City mosque minutes before a gunman stormed in and killed six people inside said the attack made him "scared out of my mind" when he realized something had happened at the mosque and he returned to the scene.

Alexandre Bissonnette, 27, is accused of attacking the mosque, killing six and injuring others. The motive for the attack was not clear, and police said Monday the investigation was ongoing.

El Refai told ABC News today it was "mind-boggling" that he just missed it. El Refai said he went back to the scene, and said it was "hard to hold back tears" when he saw people he had been praying with just minutes before had become victims of the violence.

"I actually walked past one of the first victims. ... I saw the bullet holes. It took me so long to comprehend it," El Refai said.

El Refai said one man injured in the attack had been one of his teachers. He said he was shocked to see someone he knew so well get carried into an ambulance.

A childhood friend of Bissonnette told ABC News today that the suspect appeared to him to be "Islamophobic, definitely," and "anti-feminist." Bissonnette's childhood friend, Vincent Boissoneault, said he and Bissonnette were Facebook friends, and he said Bissonnette repeatedly trolled Boissoneault's left-leaning and pro-refugee Facebook posts with negative comments.

Boissoneault said that in his comments, Bissonnette expressed anti-immigration sentiments, though Boissoneault added that he did not see Bissonnette as someone violent.

Bissonnette studied at Quebec City's Université Laval, according to the university, though he has been suspended pending the judicial process, the university said.

"Though he never talked about using political violence," Allard-Prus added.

"While authorities are still investigating and details continue to be confirmed, it is heart-wrenching to see such senseless violence. Diversity is our strength, and religious tolerance is a value that we, as Canadians, hold dear," Trudeau said in his Sunday statement. "Muslim-Canadians are an important part of our national fabric, and these senseless acts have no place in our communities, cities and country."

Addressing Canada’s parliament Monday, Trudeau said, "To the more than 1 million Canadians who profess the Muslim faith, I want to say directly: We are with you. Thirty-six million hearts are breaking with yours."

"We will get to the bottom of this," Trudeau added. "Canadians will not be intimidated. We will not meet violence with more violence. We will meet fear and hatred with love and compassion, always."

ABC News' Brian Hartman contributed to this report.