Police say the apparent gunman, who had a criminal record dating back to 1987, used a stolen 9-mm handgun in what police Chief Rod Knecht called "an extreme case of domestic violence."
The six adults, between ages 25 and 50, and two children under age 10 were found in two separate residences in Edmonton on Monday night.
The man linked to the shootings was found dead by suicide in a restaurant in the nearby city of Fort Saskatchewan on Tuesday morning.
"It was chaotic. It's horrific," Knecht said at a news conference Tuesday night. "This is a horrific event for the city … in my 39 years of policing, I've never seen anything like it."
He said the slayings were "planned and deliberate," and stressed there was no evidence of gang links.
The first body, now identified as Cyndi Duong, 37, was found by police responding to a weapons complaint in south Edmonton around 6:53 p.m. MT Monday. A man had entered the home and shot the woman, who was pronounced dead at the scene, he said.
Police then received a call to check on a man at a home at 83rd Street and 180 Avenue in north Edmonton.
"According to family, the male seemed depressed and overly emotional," Knecht said. "The family was concerned that the male may be suicidal."
When police arrived, the man wasn't there, Knecht said. Then at 12:23 a.m., police went back to the home and discovered the bodies of seven people: three women, two men and two children – a boy and a girl.
Neighbour Moe Assiff said he saw officers come out and talk to a woman sitting with a man in a white car outside the house.
"She just let out a hysterical scream. It was eerie," Assiff said. "She was screaming about her kids: `My kids! The kids!,' grabbing her hair and trying to pull her hair out. The cops then ushered her down the road into a police cruiser."
The identities of the other seven people found dead won't be released until autopsies are performed. The autopsies, including on the apparent gunman, are scheduled for Thursday.
"It's still shock here," reported CBC's Erin Collins from Edmonton. "People are trying to process it and everyone has questions about what motivated this and what could have led to this kind of tragedy."
At 2:20 a.m. Tuesday, police went to a restaurant in Fort Saskatchewan where they found a vehicle matching the description of the one owned by the suicidal male.The SUV was the same vehicle seen in the south Edmonton neighbourhood on Monday night, and was missing from the north Edmonton home.
Knecht did not release the name of the suspect, but said the man was found dead inside when police entered the restaurant at 8:45 a.m. Tuesday. Knecht said the man died in an apparent suicide. He said police are not looking for other suspects in the slayings.
Gun stolen in 2006
Police have not described the relationships between the people who died and the man who committed suicide.
Knecht said there hasn't been a mass killing of this scale in Edmonton, a city of about 878,000 where mass killings are rare, since at least 1956.
That year, John Etter Clark, a provincial politician who served as a member of the Legislative Assembly of Alberta for four years, killed his wife, son, three daughters and an employee of their family farm before taking his own life. Clark had been suffering from frequent nervous breakdowns in the years before the killings.
The gun used in the slayings this week was registered in British Columbia in 1997 and stolen from Surrey in 2006. Knecht said the apparent gunman had a business interest in the restaurant where he was found dead.
Knecht said officers had gone to the north Edmonton home twice: once this year and once in November 2012, when a man was charged with domestic violence, sexual assault and uttering threats.
Knecht also explained why police didn't enter the north Edmonton home when police were first called there. He said officers walked around the house but couldn't get in.
“They looked in windows, they checked a door and they weren’t able to get a response," he said. "We can't just arbitrarily go into that residence."
Later, they received a call from someone which gave them grounds to enter the home. That's when they found the seven bodies.
Neighbours heard fighting
People in Fort Saskatchewan became aware of the police presence early Tuesday morning. The downtown core of the city northeast of Edmonton was closed. The area has reopened, but police tape remained around the VN Express Vietnamese and Chinese Restaurant.
A Mercedes SUV with a smashed side window was parked outside.
Fort Saskatchewan resident Bonnie Peet first noticed police around 6 a.m.
“My whole road in front of my place was blocked off, so I knew something was going on and then it got lighter out ...and you see police going up and down the alleys," she said.
Another resident said that a helicopter could be heard circling overhead early Tuesday morning.
A woman who works at a restaurant across the street said she saw police drive a tactical unit through the restaurant door.
People who live next to the home in north Edmonton say a woman, a grandmother and two school-aged children lived there. The neighbours said they heard domestic arguments inside the home next door. Once they heard a man and woman fighting in the street.
"We knew the ex-husband didn't live there anymore," neighbour Murray Schermack said.
Resident Maria Melo said it's the kind of community where people say hi to one another.
"We don't visit or nothing, but it's just a good neighbourhood," she said."It's so sad to hear about that family. It's really very sad."
In the Haddow community in south Edmonton, where the first person was killed, residents expressed concern for the children who lived in the home. The three children often played with others in the neighbourhood.
Police said they are in a safe place.
"We're all disturbed by it and wondering about how the family is doing," said another resident, Frank Engley.
Also on HuffPost