Alexandre Bissonnette expressed fears during a Facebook exchange that the white race would be marginalized by immigration, the day before he was arrested in connection with the massacre at a Quebec City mosque, says a friend of the shooting suspect.

Crown prosecutors charged Bissonnette with six counts of first-degree murder and five counts of attempted murder on Monday, but neither the Crown nor police have released any information about the suspect's motives.

Former classmates and friends have described Bissonnette as gradually developing far-right views, though many say they lost contact with him in the months before the shooting.

However, Martin Robin, who met Bissonnette in 2014 at Laval University, said they interacted frequently on Facebook, including on the night before the shooting.

During their online conversation that Saturday, Robin recalled asking his friend what he thought about U.S. President Donald Trump's decision to temporarily ban entry to travellers from seven predominantly Muslim countries.

"He told me he just wanted white immigration to Canada and Quebec, exclusively," Robin told CBC News on Friday.

"He told me that in the long run, this non-white, non-European immigration may perhaps lead to the marginalization of whites. That's pretty much what struck me and what keeps popping up in my mind."

Martin Robin says he had a Facebook conversation with Bissonnette the night before the shooting. (Jonathan Montpetit/CBC)

Robin showed CBC News his Facebook account and an exchange with someone called Alexandre Bissonnette. Only Robin's side of the conversation is visible.

Bissonnette's side reads: "This message has been temporarily suppressed because the account of the sender requires verification."

A Facebook account that is believed to have belonged to Bissonnette was removed from the social networking site just hours before he was formally charged on Monday.

In response to Bissonnette's alleged comments, Robin said he told his friend that he was "crazy."

Met police investigators

Since Sunday's shooting, Robin has met with investigators from the Quebec provincial police and RCMP. He said they were seeking to find out if the suspect had received any support carrying out the attack.

"He had no help of any organization. Of that, I'm 100 per cent certain," Robin said of Bissonnette's alleged involvement.

Legal observers have speculated that ties to an organization are a necessary condition for laying terrorism-related charges, which Bissonnette is not facing, so far.

Robin also said he is good friends with Bissonnette's twin brother, Mathieu. The twins lived together in a Sainte-Foy apartment not far from the mosque Alexandre is accused of attacking.

Robin said he also had a Facebook exchange with Mathieu Bissonnette on the weekend of the shooting.

This image from Robin's Facebook account is part of his exchange with Bissonnette. The text highlighted in yellow reads, in French: 'This message has been temporarily suppressed because the account of the sender requires verification.' (Jonathan Montpetit)

They, too, discussed Trump's travel ban. Their exchange took place on Sunday night.

As the news began to circulate, Robin asked Mathieu if he had heard about the shooting, given the proximity of the mosque to his apartment.

"Yes, I saw it on the news," Mathieu Bissonnette replied. "But it's not in front of my place. It's all quiet here."

Later that night, Mathieu asked Robin if police knew "who committed the crime." When it emerged the following day that Mathieu's brother had been arrested, Robin wrote to offer his support.

Mathieu did not reply. Robin said he has not heard from him since Sunday night.