The parents of Alexandre Bissonnette, the man charged in an attack on a Quebec City mosque a year ago that left six people dead, have broken their silence, saying what happened that day is "inexcusable," but they love and support their son as he awaits trial.

Radio-Canada was given a copy of the letter penned by Manon Marchand and Raymond Bissonnette.

"Alexandre is still our son whom we love and who will always be a part of our family," they wrote. "Like all parents, we hoped to see him succeed and be happy in life.

"In a way, we also lost a son."

​Bissonnette, 27, has been charged with six counts of first-degree murder and six counts of attempted murder. He is presumed innocent, and none of the charges against him have yet been proven in court. His trial is set to begin on March 26.

Six men between the ages of 39 and 60 were killed when a gunman stormed the Quebec Islamic Cultural Centre in Sainte-Foy on Jan. 29, 2017 and opened fire as they were attending prayers.

The accused's parents said that was "inexcusable" and remains "completely unexplainable." They say have been been living "in what feels like a nightmare" ever since that night.

"So many lives were needlessly destroyed," they wrote.

In a phone interview with Radio-Canada, Marchand and Bissonnette said they waited to speak publicly until the first-anniversary commemorations were over, out of respect for the families of the victims.

"We want to give the victims their rightful place," they said by phone.

'Pain and fear have set in'

Since the night of the shooting, the parents say, their family has been shattered.

Marchand said she, her husband and their son's twin brother have sought psychological help.

More than 1,000 people took part in the anniversary vigil in Quebec City this week. Those in the first row held photos of the victims of the mosque shooting. (Peter Tardif/CBC) "Pain and fear have set in," they wrote in the letter.

In the weeks following the shooting, the family was also the target of threats. At their family home, they live with the curtains drawn and installed an alarm system out of fear of reprisals.

"There were serious threats toward Alexandre and our family," they wrote in the letter.

"Fortunately, police intervened, but we always live with the fear of a recurrence."

Support from others

​Marchand and Bissonnette said they have also sent letters of condolence to the families of the victims.

They said they were also deeply touched by the "courageous and unifying" speech of Imam Hassan Guillet during a ceremony for the victims on Feb. 3, 2017.​

On Wednesday, Guillet told CBC Montreal's Daybreak that he wasn't surprised they spoke out. He also praised the parents for their courage.

"I still stand by what I said — because it comes from the deepest part of my heart and my values — they were victims," he said.

"I don't think any of our six widows is more sad or more hurt than ... Mrs. Marchand, I think, or his father."

In their letter, Marchand and Bissonnette also thanked those who took the time to voice their support for them over the past few months.

"Their words and heartwarming gestures gave us courage and helps us keep going," they wrote.

While the parents visit their son every week at the detention centre where he is being held, they told Radio-Canada they are not sure if they will be at his trial, which is set to begin March 26 and is expected to last at least two months.