A Manitoba man arrested after a Thompson teen was fatally stabbed to death could have saved himself several months in jail had he ignored his lawyer's advice not to talk to police, a court has heard.

Justin Parker, 26, was one of three men arrested following the death of a 16-year-old boy caught breaking into cars outside a Thompson apartment complex, March 20, 2011.

Parker pleaded guilty to assault with a weapon and was sentenced Thursday to four months time served, a fraction of the 15 months he spent in custody before being released on bail.

Court heard Parker, co-accused Pierre Bessette, 25, and a third man had been watching an ultimate fighting match on television when they looked out the window and saw the victim and another youth breaking into a car Parker believed belonged to his uncle.

Parker armed himself with a can of bear spray and the three men went outside to "confront" the thieves.

One of the men shoved the victim and Parker bear-sprayed him in the face.

"Through the events that followed, (the victim) was stabbed in the heart and died," Crown attorney Brian Wilford told court.

Bessette has since been charged with second-degree murder and is awaiting trial.

Parker faced the same charge, but after a preliminary hearing was ordered to stand trial for assault with a weapon. The Crown appealed the decision and Parker was ordered to stand trial for manslaughter.

Only then did Parker agree to speak to police.

"He listened to his (then) lawyer's advise not to talk to police ... but he did so to his detriment," Wilford said. "Had he come clean he would have saved himself a great deal of time in custody. It was only when his jeopardy became manifest that he realized he stood to serve more time for a killing he had no part of."

Wilford said prior to the three men going outside, Bessette asked Parker if he should "bring a shank."

Parker "in no uncertain terms told him no" and didn't know he was armed when they went outside, Wilford said.

The third man, who is not facing any charges in connection to the killing, testified at a preliminary hearing he did not know Bessette was armed.

"The purpose of going down there was to scare them and get back what was stolen," said Parker's current lawyer Greg Brodsky. "Everybody was astounded and surprised by what happened."

Justice Rick Saull said Parker, instead of arming himself for a confrontation, should have called 911.

"This is the kind of thing that happens when people decide to take the law into their own hands," he said.