RCMP were called to this Okotoks home about an alleged domestic assault. (CBC)

An Alberta man was holding an umbrella when he was fatally shot by an RCMP officer, says the head of a team investigating the incident.

Corey Lewis, 39, was shot at six times early Sunday by a constable using an M16 rifle, Clifton Purvis, executive director of the Alberta Serious Incident Response Team, said Monday. The provincial body investigates cases of death or serious injury involving Alberta police.

Purvis said Lewis — the husband of Okotoks Coun. Naydene Lewis — was struck "several times."

Investigators said they found written material inside the Okotoks home that led them to believe Lewis was trying to die during the standoff, said Purvis, adding that Lewis legally owned four rifles and one shotgun, which were all registered.

"After having considered the content of this written material, ASIRT is investigating the possibility that the deceased intended suicide when he engaged the police," Purvis said.

Police were called to a home in Okotoks, south of Calgary, on Saturday night after a report that a man had assaulted a teenager.

Flowers were left on the lawn of the Okotoks home where Corey Lewis died. (CBC)

When officers arrived, a man armed with a shotgun threatened them, RCMP said over the weekend.

As the RCMP's emergency response team was called in, the man refused to communicate with police negotiators. He was the only person in the house as the standoff unfolded over the next several hours.

At about 2 a.m. the man emerged from the house, knelt on one knee and pointed something at the officers, Purvis said Monday. Believing it was a firearm, the officer with the emergency response team fired his rifle.

Lewis died in hospital. An autopsy has not yet been completed.

Investigation will look at use of deadly force

The object pointed at police turned out to be a dark-coloured, metre-long umbrella with a silver tip, Purvis said.

"The information police had was that he had long-barrelled weapons lawfully registered to him," said Purvis, underlining that the man had been pointing a shotgun when RCMP arrived at the scene.

Investigators interview neighbours after a fatal police shooting in Okotoks, south of Calgary. (Jennifer Lee/CBC)

"At the time that he exited the home with the umbrella, clearly all the attending police officers would have known that just hours previous he was in possession of a shotgun."

There was limited street lighting at the time of the shooting with a distance of about nine metres between the officer who fired and the deceased, said Purvis.

ASIRT's investigation will look at whether the constable was justified and lawful in using deadly force.

"To determine what his belief was at the time the umbrella was pointed at him. I mean is it reasonable to believe that it was a firearm or not? And really, that's when we try and uncover the truth," said Purvis.

Father of 4

Lewis leaves his wife and four children.

Okotoks Deputy Mayor Ralph Wilson told CBC News that Lewis was friendly and worked as an electrician. Wilson said his town council colleague will eventually issue a statement.

"We're concerned about Naydene and her kids and how they're going to cope with the situation. It's extremely traumatizing — emotionally, financially," said Wilson. "It's horrible for her to have to live with and we're just giving her our support and hoping that she gets through this OK."

Naydene Lewis, who was acclaimed as a town councillor in the 2007 municipal election, had said she would run again in this fall's vote.

With files from the CBC's Jennifer Lee