Alain Perreault, convicted in 2003 murder, granted new trial

Quebec's Court of Appeal has ordered a new trial for Alain Perreault, found guilty in 2011 of killing a 43-year-old woman he met online.

The court ruledthe judge overseeing the original case did not give clear enough instructions to the jury concerning a key piece of evidence.

Lyne Massicotte disappeared during the summer of 2003 after travelling to Quebec Cityfrom Chambly, near Montreal, to meet Perreault.

Her remains were never found.

Perreault was arrested six years later after making a confessionto an undercover police officer who was posing as a criminal in a so-called"Mr. Big" sting operation.

• How Mr. Big stings work
• 'Mr. Big' ruling a 'game changer' for those convicted in sting operations

He was convicted of first-degree murder by a jury in 2011.

Quebec's Court of Appeal had ruled that the confession was admissible, butnow says the judge should have given better instructions to the jury about what weight to give to the confession when making their final decision.

Crown prosecutors now have 60 days to decide whether or not to appeal the order for a new trial to the Supreme Court of Canada.

Challenging Mr. Big

Alain Perreault lost his original appeal in 2013.

But the case went back to the Quebec Court of Appeal in 2014 after the Supreme Court of Canada set new criteria for the use of "Mr. Big" sting operations by police.

In 2014, Canada's highest courtthrew out aconfession made to undercover police by Nelson Lloyd Hart from Newfoundland who had also been convicted of murder.