The Nova Scotia gunman who killed 22 people in a multi-community killing spree last month was in possession of two handguns and two rifles – three of which investigators believe came from the United States.

Investigators are working with the Canada Border Services Agency to trace the origins of the three guns sourced from outside the country.

Police are still not revealing the specific models or calibres of firearms used by Gabriel Wortman.

“The calibre of the weapons is not being released, because determining where and how the gunman obtained the firearms is a central part of the investigation, and we use this detailed information to verify the credibility of some of the information we receive,” said a statement from the RCMP.

Nova Scotia RCMP superintendent Chris Leather confirmed in April Wortman did not have a Canadian firearms license. In 2002, Wortman was temporarily banned from owning firearms as part of a conditional discharge of an assault charge.

Prime Minister Justin Trudeau recently cited the horrific incident while announcing a recent ban on 1,500 different “assault-style” rifles. 

While police aren’t identifying the killer’s firearms, Public Safety Minister Bill Blair said at least one of them was on the prohibition list the government just implemented.

“These weapons were designed for one purpose and one purpose only — only to kill the largest amount of people in the shortest amount of time,” Trudeau said.

“You don’t need an AR-15 to bring down a deer.”

The Liberal government has refused to define “assault-style weapons” or “military-grade weapons.” 

Meanwhile, gun rights activists have blamed the Liberals of unfairly targeting law-abiding citizens while ignoring the larger issue of criminal gun violence and policing.