Manon Marchand and Raymond Bissonnette issued an open letter Monday evening, questioning the severity of the minimum 40-year sentence handed down to their son Alexandre Bissonnette Friday and blaming the Crown for encouraging a "desire for revenge."​

On Friday, Alexandre Bissonnette, 29, was sentenced to at least 40 years in prison for killing six men at a Quebec City mosque two years ago. He will be 67 before he'll be eligible to seek parole.

Bissonnette's parents point out the sentence is the heaviest sentence imposed in Quebec since the death penalty was abolished in 1976.

"We consider this to be a very severe sentence."

They say the Crown's position — seeking six consecutive periods of 25 years of parole ineligibility — amounted to circumventing the abolition of the death penalty and extinguishing all hope of rehabilitation.

"Why deny convicts even the faintest hope?" they ask.

Bissonnette's parents said last summer when they spoke publicly for the first time that they didn't realize until it was too late how years of intimidation and bullying had affected their son's mental health.

In Monday's open letter, they point out that the bullying Alexandre endured "had devastating effects on his personality."

They say the solution to prevent another tragedy like the one perpetrated by their son is to "not lock someone up forever, but rather try to better understand and prevent bullying."

Appeal of sentence likely

Legal experts said Quebec Superior Court Justice François Huot's sentence is likely to be appealed all the way to the Supreme Court.

Quebec Islamic Cultural Centre Imam Hassan Guillet expressed sympathy for Alexandre Bissonnette's parents after the sentence was rendered.

"They are as destroyed as we are," said Guillet Friday, after seeing them in the courtroom.

Survivors of the Quebec City mosque shooting and the families of the slain men expressed their disappointment that children of the victims will have to revisit the case in 40 years, when Bissonnette will be able to apply for parole.

Read the full letter from Manon Marchand and Raymond Bissonnette below: