The six adult victims are believed to be aged 25 to 50, and the two children – one boy and one girl – under 10.
Mr Knecht said the gunman was well-known to police and had a criminal record dating back to September 1987. Police are not looking for any other suspects.
Police said the killer’s body was found on Tuesday morning at a restaurant in Fort Saskatchewan.
‘Horrific’ scene
“It appears to be an extreme case of domestic violence gone awry,” Mr Knecht said.
“This series of events are not believed to be random acts, and there is no risk to the broader public.
“These events do not appear to be gang-related, but rather tragic incidents of domestic violence.”
Mr Knecht said officers entering the house where seven dead bodies were found discovered a “horrific and chaotic” scene, and the worst crime he had seen in 39 years as a police officer.
He said the incident was the worst mass killing in the city since six people were killed in 1956.