Scott McGillivary, 26, was shot to death outside this duplex on Winnipeg's Flora Avenue on Aug. 11. (CBC)

Two teens have been charged with second-degree murder in connection to the August shooting death of a Winnipeg man outside his home in the North End.

Police announced the charges at a news conference Tuesday morning.

The accused, ages 18 and 15, cannot be identified under the Youth Criminal Justice Act. Both were already in custody on other matters when police decided to lay the charges.

Scott McGillivray, 26, was shot in the heart at about 1:50 a.m. on Aug.11. McGillivray's family said he had just stepped out into the rear area of his Flora Avenue duplex to have a cigarette.

His five-year-old son and pregnant girlfriend were inside.

Police said McGillivray encountered two males and a woman. An argument took place and McGillivray was hit with a .22-calibre bullet.

The accused will make a first appearance in court at the Manitoba Youth Centre Tuesday afternoon. The elder of the two was 17 at the time of the shooting.

The seriousness of the charge means it's up to defence lawyers to show why they shouldn't receive adult sentences if convicted.

Home invasion

Justice sources said both suspects are classified as extremely high-risk car thieves by police, meaning they have prior convictions for stealing cars and breaching court orders.

They are also accused in connection with an armed home invasion and theft of a woman's purse, which took place minutes before the shooting.

Shortly after 1:30 a.m. two males, one armed with a firearm, forced their way into a residence in the 400 block of Flora Avenue and ordered five people at gunpoint to lie on the floor while the residence was searched, police said on Tuesday. The two male suspects then fled with a purse.

They allegedly ran up the back lane near McGillivray's home and were trying to hide a handgun, the justice source said.

There was an angry confrontation and McGillivray was shot and killed.

The source said the police investigation broke open after police identified a witness, who has since made a sworn statement implicating the two suspects now charged in the killing.