KINGSTON, Ont. — After Canada’s first mass-honour-killings trial, three members of a Montreal family have all been found guilty of first-degree murder in the drowning deaths of four other family members — including three teenage sisters.

A jury on Sunday handed down its guilty verdicts for Mohammad Shafia and Tooba Mohammad Yahya, as well as their 21-year-old son, Hamed.

They had been charged with murder after the bodies of three Shafia sisters — Zainab, 19, Sahar, 17, and 13-year-old Geeti — were discovered in a submerged vehicle in a canal near Kingston, in June 2009.

Also in the vehicle was Rona Amir Mohammad, the 52-year-old first wife of Shafia, whom he married in his native Afghanistan before the polygamous family moved to Canada in 2007 and settled in Montreal.

All three suspects had faced four counts of first-degree murder.

The trial, which began in October 2011, heard from 58 witnesses and was presented with more than 160 exhibits from both prosecutors and defence lawyers. While some described Shafia as the ultimate family man, other witnesses painted a picture of strict control in the family and limited freedoms for his daughters.

A dozen independent witnesses — including Montreal police, social workers, teachers and school officials — testified the girls feared their father and even some of their siblings, who they believed were spying on them, and were depressed and desperate to get away.

On wiretap recordings played for jurors, Shafia called his daughters “whores,” “filthy” and “rotten children” who betrayed the family and Islam and did “cruelty” to Shafia by secretly taking boyfriends and by wearing revealing clothes.

Prosecutors alleged that the victims died in an honour killing orchestrated by Shafia to cleanse the shame he felt from the conduct of his daughters.

The trial also heard that Shafia’s first wife, who was living in Canada illegally, wanted a divorce from Shafia and was supportive of the daughters who were dating.

Crown lawyers alleged the three girls and Mohammad were likely pre-drowned, somewhere at the locks, before being placed into the car and pushed into the canal.

Lawyers for the accused, in their closing arguments in court, told Ontario Superior Court Judge Robert Maranger and jurors that the location and logistics were so unlikely that they argue against murder, justifying an acquittal. The lawyers also dismissed the notion of an honour killing, saying that such action is not permitted in Islam.

Lawyer Peter Kemp, who represents the eldest Shafia, said the evidence about the timing of events showed there wasn’t enough time for the accused to commit a complex multiple murder.

Kemp outlined a theory about how long it would take to forcibly drown four people at Kingston Mills — an isolated spot along the Rideau Canal — where the victims were found dead, then place their bodies inside a Nissan Sentra and push it into the water.

All of the victims had drowned, but post-mortem examinations could not pinpoint where and how they drowned.

The 12 jurors were tasked with poring over hundreds of photographs — from the scene where the victims were found; snapshots the family took while on a vacation that preceded the deaths’ and pictures taken on cellphone cameras by the victims — as well as thousands of pages of information in more than a dozen reports from medical, scientific and technical experts.

Jurors also had to consider testimony from Mohammad Shafia and Yahya, who testified at the trial. Hamed Shafia did not testify.