The bodies were "piled" on each other, Ontario Provincial Police Const. Glenn Newell told the first-degree murder trial of three people charged in the deaths of four Afghan women.
Newell said when he entered the water and got a look at the submerged car he could see there were bodies and a floating teddy bear in the car.
Newell said the driver's side door window was completely down and the car was in about two metres of water.
Inside the Nissan Sentra were the bodies of sisters Zainab, 19, Sahar, 17, Geeti, 13, and Rona Amir Mohammad, 52, the first wife of Mohammad Shafia.
Shafia, his second wife Tooba Mohammad Yahya, 41, and their son Hamed, 20, have pleaded not guilty to four counts of first-degree murder.
Newell has retrieved bodies from about 120 cars since joining the provincial police force in 1987 and said people usually try to get out, but it didn't appear that the victims had tried in this case.
"They were all piled on top of each other almost. It was very strange," Newell testified.
The fact that the window was down and the water was shallow, about a metre from the top of the car to the surface, didn't help make sense of the situation, Newell said.
"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.
Based on the position of the bodies it was impossible to determine who had been driving, but Newell noted the car was in first gear and the keys in the ignition.
"It didn't really make a whole lot of sense to me how that would happen," he said, adding he made a point of telling officers on the surface that he was "quite perplexed" about not being able to identify the driver.
Newell wasn't the first diver in the water that day.
John Moore, a recreational diver and a member of the Canadian Navy for 28 years, was there with his son and a friend on a boating trip and offered to go in.
He was given the go-ahead by an officer on scene but instructed not to tamper with the scene.
At that point, it was around 10 a.m. and nobody knew bodies were inside the submerged car police believed had been dumped in the water as a prank.
Moore saw the car had no front licence plate and damage to the driver's side and rear bumper.
He then noticed a woman doing what he described as the "dead man's float" with her back to the ceiling of the car and legs and arms hanging down.
Moore also testified being puzzled that none of the occupants, even if they couldn't swim, hadn't escaped through the driver's side window and stood on top of the car.
The car found on the morning of June 30, 2009, by Parks Canada employee John Bruce, who spotted the vehicle after raising the Canadian flag at the edge of the canal.
Bruce told court he noticed what he thought was oil pooling at the surface, saw the car and radioed for the movement of boats through the canal to stop and for someone to call 911.
Bruce's boss Kevin Nontell testified he didn't think Bruce was kidding when he said there was a car in front of opening of the locks, but couldn't believe it either.
The location of the car was odd as someone would have to jump a curb, make a series of turns and drive the car through small opening, Nontell said.
"It looked like something that would be planned," Nontell testified.
The trial continues Tuesday and is expected to last up to 10 weeks.