In a seven-volume report released on Thursday, the Mass Casualty Commission said the Royal Canadian Mounted Police (RCMP) missed red flags in the years leading up to the fatal rampage in the eastern province of Nova Scotia.

In April 2020, 51-year-old Gabriel Wortman, disguised in a police uniform and driving a fake police car, shot and killed 22 people in a 13-hour attack.

Wortman was killed by police at a gas station about 90km (60 miles) from the site of his first killings in the small, rural community of Portapique.

“There were many warning signs of the perpetrator’s violence and missed opportunities to intervene in the years before the mass casualty,” the commissioners wrote in an opening message to their report, which totalled more than 3,000 pages.

“There were also gaps and errors in the critical incident response to the mass casualty as it unfolded on April 18 and 19, 2020. Additionally, there were failures in the communications with the public during and in the aftermath of the mass casualty.”

The commission recommended increasing transparency and accountability for RCMP oversight, improving critical incident response capabilities, and focusing more on everyday policing practices.

It also called for a national review of the public alerting system and an increase in the availability of mental health services.

In the aftermath of the attack, Canadian police faced criticism for not using a provincial alert system to warn people that a gunman was on the loose – a measure residents said could have prevented some of the deaths.

Rights advocates also slammed police for what they said was a failure to properly respond to gender-based violence, after it was revealed that Wortman had a long history of abuse towards his spouse.

“We need to accept that those who perpetrate mass casualties often have unaddressed histories of gender-based, intimate partner, or family violence – which means that tackling those forms of violence must be an urgent priority,” the commission wrote in its report.

Having laid out a litany of shortcomings, the inquiry called for a fresh external review of the RCMP.

It said the federal minister of public safety should then establish priorities for the police force, “retaining the tasks that are suitable to a federal policing agency, and identifying what responsibilities are better reassigned to other agencies”.

“This may entail a reconfiguration of policing in Canada and a new approach to federal financial support for provincial and municipal policing services,” the report said.

Today, the Final Report from the Mass Casualty Commission was released. We’ll never forget the Nova Scotians whose lives were taken nearly three years ago, and we’ll continue to support those whose lives were forever changed.

— Justin Trudeau (@JustinTrudeau) March 30, 2023

The inquiry also found that Wortman illegally owned at least five firearms – three of which were smuggled into Canada from the United States, which could have been prevented with better police oversight and coordination between enforcement agencies.

“There is a lack of community knowledge about the Canadian firearms regime. It is influenced by the United States discourse centred on a right to bear arms which does not exist in our constitutional and legal structure,” the commission said.

Weeks after the Nova Scotia rampage, Canadian Prime Minister Justin Trudeau announced a ban on more than 1,500 models and variants of “assault-style” firearms across the country. Last year, Ottawa also introduced legislation to freeze handgun ownership.

On Thursday, the commission urged federal, provincial and territorial governments to adopt “legislation affirming that gun ownership is a conditional privilege”.

It also recommended that possessing ammunition and buying firearm magazines should require a licence and that the federal government should establish limits on the stockpiling of ammunition.

“Priority should be placed on reducing access to the most dangerous, high-capacity firearms and ammunition in recognition of the risks they pose and the fact they do not serve a hunting or sporting purpose,” the report said.

In a statement, Trudeau said his government would “carefully review and respond” to the inquiry’s recommendations that fall under federal jurisdiction.

“We remain deeply committed to working with the people and the communities affected to make our communities safer places to live,” the prime minister said.

“We will never forget the 22 people, including a woman who was expecting a child, whose lives were cut short on one of the darkest days in Canadian history. I hope today’s report is one of the many steps toward ensuring a tragedy like this never happens again.”

That was echoed by Scott McLeod, the brother of victim Sean McLeod.

“Nothing will bring my brother back or any of the other people in this horrible ordeal,” he said. “If this report makes a positive change nationwide it will be appreciated, I know, by families.”