Dinners in the Belkacemi household, once filled with laughter, have become heavy and disheartening since Khaled Belkacemi left home to attend Sunday prayers on Jan. 29, 2017, never to return, says the slain man's family.

Belkacemi's two adult children and his widow told a Quebec City courtroom on Wednesday their loss has also left an unmeasurable void for the country in which the university professor chose to raise his family.

"The thought that people of this calibre, with such big hearts, were killed by someone who was afraid ... this thought is impossible for me to comprehend," said his son, Amir Belkacemi.

The 26-year-old and his older sister, Megda, shared their stories on the sixth day of a sentencing hearing for the man who pleaded guilty to killing their father, as well as five other men, in a Quebec City mosque.

Amir Belkacemi told Quebec Superior Court Justice François Huot the mosque in the city's Sainte-Foy neighbourhood was part of his day-to-day life, growing up.

Khaled Belkacemi was a professor in the department of soil and agri-food engineering at Université Laval, training hundreds of researchers, his daughter Medga testified Wednesday. (Laval University INAF)

Now he can no longer go through the front door without looking at the place his father fell, struck by a single bullet, at the far end of the vast prayer room.

"My father, this giant, who wasn't finished with life," he said.

Seeking peace

Amir Belkacemi told Huot he wanted to speak his truth and wanted to leave the courtroom with a clear message.

"People who go through the process of coming to Canada, who sacrifice their lives, don't do this to inflict terror. They do it to build better lives for themselves here."

The young man's comments were a response to statements made by Bissonnette during his police interrogation, played for the court early in the sentencing hearing, in which the 28-year-old described how he had been anxious about his own family becoming victims of a terror attack.

In the video, Bissonnette said those feelings reached a peak when he saw media reports about the Canadian government planning to allow more refugees into the country.

"In the end, it was my family who was attacked," Megda Belkacemi said in a strong voice, reading from a written statement that was entered as evidence by the Crown.

Amir Belkacemi tells the judge: “Alexandre Bissonnette turned his back on his humanity ... This man, behind me, is a monster. I believe monsters have no place among us.” After those words he turns to glare at the man who killed his father, then quietly returns to his seat. —@jbernstien

The 29-year-old lawyer explained how her parents decided to leave Algeria in 1994 to protect their children, as that country was being devastated by violent extremism.

That year, the rector of the university in Algiers where her father was working was assassinated, the same morning the two men were to meet in the rector's office.

This was enough to persuade Khaled Belkacemi and his wife to pack up and leave.

"But the violence my parents fled from caught up with us," Megda Belkacemi said.

Like her father, she described herself as an enthusiastic, cheerful person — a part of her personality she says she lost the day of the attack.

Research work 'to improve lives of others'

Belkacemi's mother, Safia Hamoudi, said in addition to losing a husband, she lost an esteemed colleague.

Hamoudi and Belkacemi worked together on numerous research projects in the food engineering department of Université Laval.

Safia Hamoudi, centre, spoke at a memorial to the slain men on the anniversary of the mosque shooting in January 2018. Her son Amir Belkacemi, back left, and her daughter, Megda Belkacemi, back centre, stood with her in support. (Jacques Boissinot/Canadian Press)

Hamoudi said her husband dedicated his life to improving the health of others, from developing trans fat-free hydrogenated oil to finding sodium-free substitutes for salt.

"My life has lost all meaning. I have lost all zest for life," Hamoudi said, her back to the man who killed her husband.

Her eldest son chose to stare straight at Bissonnette as he left the witness box, moments after calling him "a monster" who had lost his humanity the moment he decided to kill other human beings.

Amir Belkacemi said he needed to look into his eyes to see if he was right.

"Actually I saw nothing. Nothing."

Bissonnette also pleaded guilty to six counts of attempted murder, for shooting in a crowd of more than 40 people, including children.