Young engaged Canadian couple Carissa MacDonald, 27, and her fiancé, Aaron Stone, 28, were shot dead on Saturday on their front lawn during argument with their landlord

Police were called to the home at 5:40pm Saturday after the pair were killed on the lawn in front of the house in the Stoney Creek district of Hamilton, Ontario

The pair had been fleeing from their landlord Terry Brekka, 57, who had argued with the couple about mold in the basement where they lived

Brekka who lived upstairs in the same home, then barricading himself in before being killed in a shootout with police

Police said the tenants complained about the issue sometime before their landlord shot them

Victims: Carissa MacDonald, 27, who worked as an educational assistant at a local Catholic school, and her electrician fiancé, Aaron Stone, 28, were both shot dead by their landlord on Saturday in Ontario, Canada

A Canadian couple who were engaged to be married, shot dead by their landlord on the front lawn of their home, Saturday, in Ontario, Canada.
Police were called to the Stoney Creek district of Hamilton, Ontario, at 5:40pm Saturday after the pair were shot dead on the lawn in front of the house.
The couple who lived in the basement had been fleeing from the rage of their gun wielding landlord who lived upstairs, during an argument, before they were shot.
Responding officers found 27-year-old Carissa MacDonald, who worked as an educational assistant at a local Catholic school, and her electrician fiancé, Aaron Stone, 28, dead on the front lawn. 
The couple pair rented the basement of a home belonging to Terry Gerald Brekka, 57, who lived upstairs from them. They pair had been running away from the house when they were shot to death following an argument over mold with Brekka.

Police called out to the Stoney Creek district of Hamilton, Ontario, at 5:40pm Saturday found after the engaged pair of Carissa MacDonald and Aaron Stone [photo], shot dead on the lawn in front of their rental home

The couple got into a dispute with Brekka, stemming from a ‘disagreement surrounding issues within the house,’ said Det. Sgt. Steve Bereziuk, of Hamilton Police’s Major Crime Unit.
Authorities were called to the house in the Stoney Creek district of Hamilton, Ontario, at 5:40pm on Saturday, amid reports of gunfire.
The suspect then barricading himself in before being killed in a shootout with police.
‘(They were) both hardworking people, adding to the tragedy of this event,’ he said.
Neither the couple nor Brekka was known to police, Bereziuk confirmed, which makes what happened ‘a little bit more shocking.’

Murderous landlord Terry Brekka was killed in a shootout with Ontario police after he killed both of his tenants in Hamilton, on Saturday

Investigators placed markers on the ground at the scene of a double-homicide after an engaged couple, both in their twenties, were shot dead by their landlord in Hamilton, Ontario on Saturday

The victims lived in the basement of this house in Stoney Creek, Hamilton, Ontario owned by their killer

For Sgt. Bereziuk the murder of the young couple was deeply shocking.
‘As you can well imagine these are not people that this should happen to,’ he said.
‘They’re not involved in any level of criminality or lifestyle that may lead to an incident like this. They’re truly innocent.’
Hamilton police say the dispute between the landlord and couple it thought to have been related to a complaint about mold in their rental unit.  

Victims: Aaron Stone [left], was an apprentice electrician with the International Brotherhood of Electrical Workers, while Carissa MacDonald, a Mohawk College graduate, worked at the Brant Haldimand Norfolk Catholic District School Board

After shooting the couple, Brekka barricaded himself inside the home with “multiple firearms” that were registered to him, including hand guns and long gun rifles.
Bereziuk said the police spent ‘considerable time’ trying to negotiate a ‘peaceful resolution’ with Brekka, but he opened fire on them at around 10pm and was shot dead.
The standoff ended in ‘an exchange of gunfire’ with a police officer, according to the Special Investigations Unit [SIU].

Hamilton police say the dispute between the landlord and couple it thought to have been related to a complaint about mold in their rental unit

On Monday, Det. Sgt. Steve Bereziuk told CBC News how the tenants complained about the issue sometime before their landlord shot them.
‘That’s what we’re investigating to see if that’s in fact what this was about,’ Bereziuk said. ‘I think the big question is why did this happen, a lot of people want to know that. We may never be able to answer that.
‘It’s a perfect storm of tragedy in this case because you can’t predict something like this and you can’t prevent it,’ Bereziuk went on.
‘Because nobody was on our radar, at least for the Hamilton police. It makes it difficult to understand how things can [happen], certainly with respect to a landlord-tenant dispute.’

Police collect evidence at the scene of a homicide investigation. A search of the shooter’s home led to the recovery of a cache legal weapons

The couple are pictured at their home at the rear of the property had been running from their landlord during an argument about mold in their basement home

Aaron Stone was an apprentice electrician with the International Brotherhood of Electrical Workers, while Carissa MacDonald worked at the Brant Haldimand Norfolk Catholic District School Board for the past three-and-a-half years and was a Mohawk College graduate.
‘Our prayers are with her family and with all individuals impacted by this tragic situation,’ said school board spokesperson Tracey Austin.
Families and staff were informed of the ‘incredible loss,’ Austin said.

Members of the Special Investigations Unit (SIU) at the scene of a double-homicide investigation in the area of Jones Road and Barton Street in Hamilton, Ontario on Saturday. The alleged shooter was also killed during a standoff with police

Local resident Sandra Chaisson, who has lived in the neighborhood for more than four decades, said the landlord bought the house on Jones Road from her grandparents. She said that Brekka lived in the house for more than 20 years having bought the property in 2003 for $115,000.
‘He was very quiet. A very quiet man. I didn’t see him much, just to wave hello, but I haven’t seen him for a long time,’ she said.
Tony Greenly, a next-door neighbor called Brekka as ‘bad news’ noting how he would often stand on top of his roof, watching them. 
Greenly said the ‘harassment’ spurred him to build a carport to block Brekka’s view, adding that, ‘It’s like we couldn’t breathe in our own backyard.’
‘I was terrified,’ Joanne Greenly, Tony’s wife added as she recalled the shooting. ‘That could’ve been us. He could’ve gotten mad enough to actually get them [the shotguns] out. I feel sorry for the young couple — so young.’
A search of Brekka’s home led to the recovery of multiple legal weapons.