Ontario jurors saw for themselves Tuesday how the bodies of three teenage sisters and another family member looked suspended in water in a car at the bottom of a canal.

Tooba Mohammad Yahya and husband Mohammad Shafia and their son Hamed Mohammed Shafia are escorted by police officers into the Frontenac County Court on the first day of their murder trial in Kingston, Ont. (Sean Kilpatrick/Canadian Press)

But the girls' mother, one of the people accused of killing them, asked to leave the courtroom so she didn't have to see the eerie video shot by a police diver.

Sisters Zainab, 19, Sahar, 17, and 13-year-old Geeti Shafia were discovered with their polygamist father's first wife, Rona Amir Mohammad, 50, in a car on June 30, 2009, in the Rideau Canal near Kingston, Ont.

The girls' mother, Tooba Mohammad Yahya, 41, their father, Mohammad Shafia, 58, and their older brother, Hamed Mohammad Shafia, 20, have each pleaded not guilty to four counts of first-degree murder.

The Crown alleges the Montreal family thought their daughters betrayed them by having boyfriends, so they killed them and staged the scene to look like an accident.

Underwater video shows submerged victims

The 14-minute underwater video shot by provincial police Const. Glenn Newell was uneventful for the first 10 minutes, but when he pans up past the door panel, a pair of legs can be seen in the first in a series of grisly discoveries.

The jury could then see the head of one of the victims, facing down and with hair obscuring her face. Blankets, a purse, a yellow bag, a torso and the hand of a victim are seen in the passenger side window on the driver's side.

The jury watched a video shot underwater by police divers who retrieved the victims from a submerged car in this Kingston Mills lock in 2009. (Sunny Freeman/Canadian Press)No one is sitting in the driver's seat.

In the backseat are Rona Amir Mohammad and Sahar, who court has heard was "given" to Mohammad by Yahya to raise as her own, because Mohammad couldn't have children. The two were especially close, court has heard.

Their bodies were found sitting side by side, their heads touching.

Newell testified on Monday that although one car window was open, it appeared that none of the victims had tried to get out of the vehicle.

"I would think it would make it very simple for somebody, who could get to that window, to get out of that window," he said.

The cause of death for all four victims was drowning, but it isn't possible to say for certain that they drowned in the canal where they were found, the Crown has said. Three of them had bruising on the top of their heads.

The Crown theory of the car's path is that it would have had to travel past a locked gate, over a concrete curb and a rocky outcrop and then make two U-turns to end up in the lock of the canal.

Motel manager testifies about room check-in

The family had been on their way home from a trip to Niagara Falls, Ont., when the car wound up in the canal.

A Kingston motel manager testified Tuesday that when Shafia and Hamed checked in to two rooms for the family that night, at first Shafia said there would be six guests. There were 10 people on the family trip.

An expert will be called later to testify about so-called honour killings and how in extreme cases, killing can be seen in some cultures as a way to restore honour to a family.

Disobedience by a female member of the family can cause shame and taint family honour, the expert is expected to testify.

The family immigrated to Canada in 2007. They left their home country of Afghanistan in 1992 and lived for a number of years in Pakistan, Australia and Dubai before coming to North America.

The trial is expected to last up to 10 weeks.