SAINT-JEROME - A five-year-old boy pleaded with his father to stop stabbing him as the blows kept raining down, but the man continued until the child was dead, the final Crown witness at Guy Turcotte's trial testified Friday.

Luc Tanguay testified that Turcotte, who is charged with murdering his two children, told him he killed them so they wouldn't have to see him dead after his own suicide.

Tanguay was a "life coach" employed by Turcotte and his wife, Isabelle Gaston, to help their failing marriage.

He testified at Turcotte's jury trial Friday he met with him two weeks after the slayings.

Tanguay said Turcotte told him what happened the night that Olivier, 5, and Anne-Sophie, 3 were killed in February 2009.

Tanguay said the accused told him that Olivier, who was still awake, pleaded with his father for his life as he was being stabbed.

According to Tanguay, Turcotte wanted to commit suicide that night and take the children with him because he didn't want them to find him dead the next day.

Tanguay testified that Turcotte also said he was remorseful for what had happened.

Tanguay had tried to help Turcotte and Gaston through their marital problems.

The trial has already heard their rocky 10-year relationship ended when Gaston started a new relationship with her personal trainer, Martin Huot.

Turcotte was scandalized by his failed marriage, and the slayings occurred less than a month after the split.

Turcotte has pleaded not guilty to two counts of first-degree murder. He admits to causing their deaths but has denied intent.

They were stabbed in a rented home in Piedmont, Que., where Turcotte was also discovered after having ingested washer fluid.

The emotionally charged trial now switches to the defence on Monday and Turcotte himself could be called on to testify.

If found guilty of the first-degree murder, Turcotte would be sentenced to life in prison.