The report released Thursday says Dwayne Poirier strangled his wife, Cathie Heard, and then removed a cap from a natural gas line. Their home in northeast Edmonton exploded like a bomb in June 2010.
Poirier and two men who lived next door were killed. The blast caused $3.8 million in damage to 41 homes in the neighbourhood.
Provincial court Judge James Wheatley says Poirier, 46, and Heard, 47, had severe emotional problems and had obtained several emergency protection orders against each other, which they always discontinued when they got back together.
Wheatley notes in his report that police gave evidence at the inquiry that one-quarter of their investigations involve domestic violence.
"One must wonder if, in fact, 25 per cent of all police business involves domestic violence, whether the manpower allocated to (the Edmonton police) domestic offenders crime section is sufficient to deal with this ever-present problem within our society," Wheatley writes.
A fatality inquiry does not lay blame, but makes recommendations to prevent future deaths.
Wheatley recommends that Edmonton police consider setting up a unit to intervene in family violence cases before they get serious and that they use a Calgary model as an example.
He says police services should begin training officers about domestic violence when they are recruits and continue training once they are in the field.
Shortly after killing his wife, Poirier expressed remorse at what he’d done in an email sent to a mental health worker.
Heard’s body was found rolled in a carpet in the home and bound with duct tape.
During the inquiry, Heard's father, George Robinson, testified that Poirier verbally abused her in front of her children.
Wheatley also endorsed a recommendation made by the mothers of two of the victims.
"Programs should be instituted in schools within Alberta to help children recognize instances of domestic violence, to learn how to report them and to protect themselves and others from the consequences of such violence."
Edmonton police Staff Sgt. Sean Armstrong said the service is already doing much of what the report recommends.
Armstrong said there are no immediate plans to form a unit to intervene in family disputes before charges are laid. He said shelters and community groups that deal with family violence need to work more closely together and with police.
"A lot of the recommendations deal with the police, but it is no way a police-only issue," Armstrong said. "It is a mental-health issue. It is a community issue."
The report comes about two months after a mass murder in Edmonton. Phu Lam shot eight people, including his wife, eight-year-old son and three-year-old niece, before killing himself.
City police have said they receive about 7,600 calls of domestic violence each year and, while that number has remained static, the level of violence seems to be increasing.