Guy Turcotte murder trial: Ex-wife Isabelle Gaston testifies

On the day her children were killed, Isabelle Gaston was toldbyGuy Turcotte:"You want war, you'll get it," Turcotte's ex-wifetold the jury on the first day of her testimony.

Gaston, the mother of two children stabbed to deathin 2009, took the witness stand on Mondayat thesecond murder trial of Turcotte, her former husband.

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Gastonrecountedsome of the couple's conflicts leading up to the deaths of five-year-old Olivierand three-year-oldAnne-Sophie, whowerefound dead by police in Turcotte's Piedmont home.

The childrenhad been stabbed 46 times.

Gaston described her relationship with Turcotte as having "ups and downs," especially beginning in 2008.On February20, 2009, Gaston testified that she told Turcotte she had changed the locks at the family home.

Turcotte told her she didn't have the right, and he yelled at her over the phone, she told the court.

The next morning, the bodies of Anne-Sophie and Olivier were found.

The trial, taking place in Saint-Jrme, Que., was briefly suspended Mondaymorning and resumedin theafternoon.

Turcotte admitted to causing children's deaths

Last week, Turcotte, a former cardiologist, admittedcausing his children's deathsin an 11-page documentsubmitted to the court. The document listed facts and evidence that both the defence and the Crown had agreed to accept.

Prior to the document being submitted, police witnesses including one of the officers who found the children's bodiestestifiedlast week.Two knives, an opened bottle of windshield wiper fluidand graphic images of the crime scene, among other pieces of evidence, were presented to the jury.

The jury has been warned to expect some gruelling emotional testimony throughout the trial, which is expected to take about three months.

JusticeAndrVincentordered the jurors to ignore anything they heard about the case outside of the courtroom, saying they must concentrate only on the evidence given at the trial.

Background on legal battle

Last week, Vincent began proceedings by readingthe charges to the12 jurorstwo counts of first-degree murder.

In 2011, Turcotte was found not criminally responsible for the deaths and was remanded to thePinelInstitute, a Montrealpsychiatric facility. He was released in December 2012.

The verdict inTurcotte'sfirst trial was thrown out after the courts found the initial judge had made a mistake in communicating with the jury.

An appeals process that went all the way to the Supreme Court resulted in Turcotte's re-arrest last year.