HALIFAX -- Nova Scotia RCMP say the shooter in last week’s mass killing wore an authentic uniform during his 13-hour rampage, though investigators have yet to determine how he acquired the clothing.

Nova Scotia RCMP Supt. Darren Campbell said during a briefing on Tuesday that Gabriel Wortman, 51, had four former police vehicles he acquired through auctions, including the one used in the mass killing, which was obtained in the fall of 2019 and was modified with decals and police lights.

Police confirmed he was wearing an authentic RCMP uniform at one point during the killings and changed clothing several times.

“We've learned that the gunman was a collector of many things, including police memorabilia and was in possession of multiple pieces of police uniforms from a variety of agencies,” Campbell said.

Police have yet to confirm where the shooter obtained these uniforms, but Campbell noted there are plenty of avenues to do so, including surplus stores and online auctions.

Campbell also said the shooter was related to retired RCMP officers, but that “at this time, there’s no indication that a former member of the RCMP provided assistance to the gunman or provided them with any police equipment.”

The shooter’s rampage began on the night of April 18, when he assaulted and bound his common-law spouse, who managed to escape and hid overnight in the woods near Portapique, N.S.

Campbell said officers have had several opportunities to interview the woman and “intend” on conducting further interviews with her as the investigation progresses.

“She is a critical witness and it will take some time,” he said. “We are going to spend our time with her. We want to understand everything that she knows.”

After the woman escaped, the attacker then began shooting and setting the homes of several neighbours on fire. Police said Tuesday that eight of the shooter’s 22 victims were found in buildings that had been set on fire.

During the news briefing, officers said nine victims had been killed in fires, but later clarified that they could not yet determine the cause of death for any of the victims and that only eight had been found inside burned structures.

Campbell said that officers now believe the shooter escaped the area of Portapique, N.S. the night of the shooting by driving through a field just a few minutes after police arrived and eventually spent the evening near an industrial area in Debert, N.S.

Officers do not yet know the sequence of events from the time he arrived in the industrial area, until he left Debert the following morning, but from there the shooter made several stops in central and northern Nova Scotia, leaving behind 16 crime scenes and an additional nine victims. The shooter was later shot and killed by police at a gas station in Enfield, N.S.

Police said Tuesday that of the 16 crime scenes they had been investigating, all but five have since been released. Police also said the shooter killed several of his victims’ pets during his rampage.

Two of the scenes investigators have examined are the shooter’s home and business in Dartmouth, N.S., which appeared to have been vacated by the time officers arrived.

“It appeared as if he was mainly using the Portapique residence as his permanent or his more frequented address at this time,” Campbell said.

Officers are currently in the process of interviewing more than 435 witnesses who have come forward thus far with information on the investigation.

The provincial RCMP investigation has expanded to include help from other RCMP detachments across the country, the Halifax Regional Police and the Canadian Border Services Agency.

Campbell would not confirm why the CBSA has been brought into the investigation, but did note that he had said previously that all but one of the shooter’s several weapons had been purchased in the United States.

With files from The Canadian Press