A handout photo from the Laval police department shows Adele Sorella. THE CANADIAN PRESS/HO - Le Service de police de Laval

LAVAL, Que. - A Crown attorney told jurors Monday that Adele Sorella was the last person to be seen with her daughters before they were found dead in the family home.

In his closing arguments, Simon Lapierre repeated the Crown's theory that Sorella alone had the opportunity to kill Amanda, 9, and Sabrina, 8, on March 31, 2009.

"She is the only one who could have committed this offence, and it is on that basis that I submit to you that we have proven her guilt," he told the jury.

Lapierre said it was impossible that another person entered the family home and killed the girls, noting that there was no evidence of a break-in or struggle and nothing had been broken.

The prosecutor also told the jury that the Crown is not required to establish a motive for the crime.

The girls' bodies showed no signs of violence, and the cause of death was never determined. But Lapierre said the Crown does not need to prove beyond a reasonable doubt the cause of death, whether it involved a hyberbaric chamber in the house to treat Sabrina's juvenile arthritis or something else.

He said there is no reason to think the deaths were accidental. He reminded jurors of a first responder's testimony that the girls were found lying side by side in their playroom, as if they had been laid there.

Sorella was supposed to be with her children, Lapierre said. "But where was she?" he asked. That morning, Sorella's mother said goodbye to her daughter and granddaughters as she left the house for an appointment. Sorella testified that she has little memory of the what happened that day. She was found hours later after crashing her car into a pole.

The prosecutor challenged Sorella's credibility by highlighting elements of her testimony that were contradicted by other witnesses.

He also asked the jurors to consider the hyberbaric chamber, which a pathologist said was a possible cause of death by asphyxia. He said there is no evidence the children put up any resistance. Lapierre asked whether it is reasonable to think that a stranger could have placed the girls in the chamber without a struggle.

Last week, Pierre Poupart, one of Ms. Sorella's lawyers, spent four days going over the reasons his client should not be found guilty. Her trial on two charges of first-degree murder began in November.

Poupart stressed that the cause of death was not established, and he pointed to evidence that he said suggests someone else could have entered the house.

If, however, the jury concludes that Sorella, 53, killed her daughters, Poupart is arguing she should be found not criminally responsible because of a mental disorder. Medical experts testified that Sorella experienced a dissociative episode the day of the killings.

Poupart said that even if the jury does not believe she meets the criteria to be found not criminally responsible, her mental state had an impact on her ability to form the intent to commit the crime.

The children's father, Giuseppe De Vito, was on the run from the police when his daughters died. He had left the home in 2006 after being targeted by an organized crime investigation. He died in prison in 2013.

Superior Court Justice Sophie Bourque will give instructions to the jury Wednesday, after which deliberations will begin.

News from © The Canadian Press, 2019