Perpetrators of honour killings do so under the mistaken belief that their actions will restore respect for their family in their community, says a Canadian expert on the phenomenon.

On Sunday, Mohammad Shafia, 58, his wife Tooba Yahya, 42, and their son Hamed, 21, were each found guilty on Sunday of four counts of first-degree murder in the deaths of the Shafias' three daughters and the older man's first wife.

The Crown had argued the deaths were honour killings, an attempt to restore the family's dignity in the wake of the girls' rebellious behaviour. The family denied these claims, but Justice Robert Maranger called the killings an "honourless crime" when addressing them after the verdict was handed down, saying the victims were killed because they "offended your completely twisted concept of honour…that has absolutely no place in any civilized society."

Amin Muhammad, a professor of psychiatry at Memorial University in St. John's, Nfld. and an expert on honour killings, said such a crime is usually committed when a female establishes a relationship with a man outside of her family.

Muhammad told CTV News Channel on Sunday that the Shafia case, in which the Crown alleged that the father was angry that the girls had boyfriends and rebelled against some family rules, fits the bill for such a crime.

"Eliminating the victim, they feel that this is the right way to restore the honour," Muhammad said after the verdicts were handed down. "But as you can understand there are some psychological dimensions also to this aspect, that these people who would commit this crime understand this particular honour in a faulty way, would have some psychological disturbance in their own personality and in their life."

According to Muhammad, those who commit honour killings "believe that the people in their community, in their tribe or in their country of origin will hold them in high respect."

Sisters Zainab, 19, Sahar, 17, and Geeti, 13, along with Shafia's other wife Rona Amir Mohammad, 52, were found dead in one of the family cars at the bottom of a Kingston canal in June 2009.

The family said the women had gone out for a joyride and become lost, falling into the canal by accident. The Crown contended that the Shafias killed the women and staged the scene to look like an accident.

Muhammad said that while the family patriarch would have been the driving force behind the killings, his wife's involvement comes as no surprise.

"I'm not surprised because in many such cases accomplices are women: mother, a grandmother, sister, and among the male members, it could be a brother, son, father, uncle or any other relative," he said. "But women are also co-perpetrators under such situations."

Kingston Imam Sikander Hashmi said Islamic teaching doesn't condone honour killings.

"(It's) certainly unacceptable under Canadian law and I think it's inhumane," he told CTV News.

According to Muhammad, honour killings are "globally prevalent," with about 5,000 women killed each year. In Canada, about a dozen cases have so far fit the bill for an honour killing, and he said more can be expected amid heightened awareness of such crimes.

Other high-profile cases include the murder of 16-year-old Aqsa Parvez, who was strangled to death at her family's Mississauga, Ont. home in 2007. Her father and older brother pleaded guilty to second-degree murder. The teenager had run afoul of her father's strict rules by refusing to wear the hijab and running away from home.

However, the Shafia verdict sends a message that honour killings will not be tolerated in this country, Muhammad said.

"Those people who are even thinking about it or are even having those thoughts in their mind should be warned now by this verdict that Canada is not going to accept this particular term and cannot allow first-degree or heinous crimes under this particular term," he said. "And I think this is a lesson to be learned for those people who come here with this mindset."

Farzana Hassan, past president of the Muslim Canadian Congress, echoed Muhammad.

"Immigrant communities need to shed those attitudes when they come to Canada or else go back," she told CTV News.

With a report from CTV's Omar Sachedina