The Crown failed to prove its theory that the deaths of four women in a Kingston, Ont., canal were "honour killings," a defence lawyer argued Tuesday during closing arguments of the Shafia family murder trial.

The defence was first to address the jury at the close of the trial of Mohammad Shafia, 58, his wife Tooba Yahya, 42, and their son Hamed, 21. They are each accused of four counts of first-degree murder in the deaths of Shafia sisters Zainab, 19, Sahar, 17, and Geeti, 13, and Shafia's first wife, Rona Amir Mohammad, 52.

All have pleaded not guilty.

Shafia's lawyer, Peter Kemp, said that despite weeks of testimony and considerable evidence, the Crown left too many unanswered questions for the jury to reach a guilty verdict.

In particular, Kemp told reporters outside court, the Crown failed to prove the deaths were a result of murders committed in an attempt to restore family honour after the children rebelled and were supported by their father's first wife.

"My position is that they just missed the boat. They grabbed a hold of a theory and aimed all the evidence at that particular theory," Kemp said.

Yahya's lawyer, David Crowe, told reporters said that his client "had a very close relationship with her children," and therefore had no motive to kill them.

Kemp also said the Crown failed to prove that any murder had been committed.

"The crown's theory is that they were already dead or unconscious when they were put in the locks, and so all the drowning did, if they drowned in the locks, is finish it off, they were killed somewhere else," he said. "Where? Why? How?"

Kemp told court that allegations Shafia abused his children were unfounded, and the deaths were nothing more than an accident.

Kemp also told jurors that they can't know for sure who was at the scene the night the women died other than the four victims, so there's not enough evidence to convict Shafia of murder.

"The Crown has the burden of establishing his guilt beyond a reasonable doubt...With all these unknowns it's only speculation that can provide answers and speculation, ladies and gentlemen, is not proof beyond a reasonable doubt," he said.

"Mohammad Shafia has not had the case proven against him and should be acquitted."

During his closing remarks, Kemp laid out a possible murder scenario, which had Shafia taking each woman from the car one at a time, drowning them, hiding their bodies until he was finished and then moving the bodies back to the car and pushing it into the canal.

But Kemp said there was not enough time for Shafia to follow through on such an elaborate act.

He also said Shafia could have chosen an easier spot to stage an accident than the Kingston Mills locks.

Kemp said the jury can't ignore the possibility that an accident did occur because it appears the women made no attempt to escape the vehicle despite there being an open window.

"It's pitch black, it's raining, there's no moon, there's no stars...water is gushing in through a window," he said. "You would immediately become disoriented. You wouldn't know where up was. You wouldn't know where down was...They'd have been climbing all over each other trying to get out of the vehicle and they weren't successful."

In his closing statement, Crowe refuted the Crown's claim that the deaths were honour killings. He reviewed testimony from an expert on honour killings and said the circumstances of this case don't fit the definition of the term.

Crowe also said Shafia had forgiven his daughters' transgressions.

"The concept of honour killing has no application to the events before you," Crowe told the jurors. "It should be disregarded in its totality when you're deliberating."

Crowe also told the jury that police wiretap evidence indicates Yahya did not know the women had died.

"God so took away their common sense," Yahya is heard saying after police showed the family the scene on July 18, 2009. "They didn't think. They had no business there."

Language barrier

Earlier Tuesday, Beauchemin told CTV's Canada AM that there was a lot of information for both sides to summarize before the case can be handed to the jury.

"There have been 58 witnesses, 162 exhibits, 10 weeks of testimony, so there's quite a bit to wrap up here today," she said on her way to the Kingston court house.

The final submissions are expected to take two full days. The lawyer for Hamed Shafia will make his final submission on Wednesday, as will the prosecution.

The judge will then spend the better part of Thursday giving the jury final instructions, taking the time to explain the law and presenting the options to the seven-woman, five-man jury.

Beauchemin told Canada AM that one of the aspects that has made this case difficult is the language barrier. Most of Yahya and Shafia's testimony was delivered in Dari, their first language, and a team of interpreters had the task of translating the testimony to the court.

"One of the last witnesses was a linguistics expert who talked about the difficulty in trying to translate and rendering the exact meaning of some words, and the expressions that were used," she said.

The bodies of the three Shafia sisters and Mohammad were found June 30, 2009, in a car submerged in a canal in Kingston, where the family had stopped on their way home to Montreal from a trip to Niagara Falls.

A pathologist testified that the cause of death for all four was drowning, though he couldn't conclude if they drowned in the canal where they were found. The Crown alleges the four were dead before their car hit the water.

The Crown painted a picture of a family that was at war with each other, with the parents unable to control their three rebellious daughters, and at odds with Mohammad, who was supportive of the girls.

The court heard from teachers, child protection workers and police about reports from the girls that they were afraid of their father and brother and either had wanted to leave the family home or had tried to run away.

The court also heard from police and technical witnesses who testified it was unlikely the car could have fallen into the canal by accident, that it would have had to travel through tight spots to make it to the spot where it was found.

Yahya and Shafia refuted all of the Crown's evidence, insisting there was not way they would have ever killed their own children.

They both testified that they knew nothing of what happened that night, though Yahya was forced to admit she had initially lied to police when she said she and the two Shafia men had indeed been at the canal that night.

Hahmed never took the stand in his own defence.

The family insists the deaths were an accident. But the defence presented two versions of events, reports Beauchemin.

"One of them is that it was an accident that 19-year-old Zainab took the keys to the car, took the car on a joyride, and they never saw her again," she said.

"Then there was a version that emerged where Hahmed said he actually witnessed the accident. He told someone that the girls had taken the car, that he had followed them and witnessed the accident. He tried to dangle a rope over the edge to help them out, but then had driven off when he had seen that there was nothing he could do. He then didn't talk about the accident because he feared what would happen.

"This is a version of events that Hahmed presented to one of the witnesses, and the witness testified in court that he heard this version from Hahmed," she said.

With a report from CTV's Genevieve Beauchemin and files from CTVNews.ca's Angela Mulholland