The Royal Canadian Mounted Police said the gunman, 30-year-old Mark Vijay Chahal, entered a home on Friday and opened fire as relatives prepared for the wedding that day of his wife's sister.
"The motive that we're pursuing ... is that he chose to take revenge on the entire family," RCMP Sergeant Doug Hartl said on Saturday.
Chahal's estranged wife, 25-year-old Rajwar Kaur Gakhal, and the bride- to-be, 24-year-old Balwinder Kaur Gakhal, were among the victims in this quiet city about 180 miles north-east of Vancouver.
Witnesses described how Chahal opened fire with a .40-calibre semi-automatic handgun and a .30-calibre revolver. "He had two guns. One in each hand, just like the old western-style shooters, blasting away," neighbour Rick Young said.
"He was only a few yards away. He turned and looked me in the eye. I thought I was going to die. He had a full opportunity to plug me full of holes. But he just turned away from me and went around again to the back of the house and then fired some shots at the back."
Police found six people dead when they arrived at the house. The head of the family, 50-year-old Karnail Singh Gakhal who moved to Canada more than 20 years ago from Punjab, India, lay dead in the drive.
Three other victims died later in hospital. An elderly woman and a six- year-old girl remain in hospital with gunshot wounds. Two children were unharmed.
Chahal committed suicide soon after the shootings at a nearby motel. He left a note apologising for the massacre.Reuse content