HALIFAX -- Three Nova Scotia senators are calling on the province to join with Ottawa to launch a joint inquiry into the mass shooting in April that claimed the lives of 22 people, saying the investigation must address related social issues through a "feminist lens."

Senators Mary Coyle, Colin Deacon and Stan Kutcher issued a statement Tuesday confirming they have sent a letter outlining their request to federal Public Safety Bill Blair and Nova Scotia Justice Minister Mark Furey.

"Canadians deserve to know what happened," the letter states.

"A joint inquiry would help everyone better understand what transpired and to learn from this tragedy. If properly conducted, the joint inquiry could lead to changes to policies, practices and procedures and hopefully give us the tools to prevent future tragedies of this nature."

Last week, Furey indicated that some kind of federal-provincial review or inquiry was in the works, but the specific nature of the investigation remained unclear. An announcement was expected this week.

The senators' letter says an "equally-led public inquiry" is needed to explore issues beyond the role of the RCMP.

The senators note that the gunman assaulted his spouse early in the rampage, which is why the inquiry must deal with intimate partner violence.

"We must seek to change how the current system addresses this violence," the letter says. "Following a tragedy, the warning signs become abundantly clear, but law enforcement and other responders must be equipped to intervene before harm is inflicted."

Their letter includes a list of key questions the senators say must be answered by an independent public inquiry.

Among other things, the senators say Canadians want to know what role, if any, the COVID-19 pandemic played in the tragedy.

As well, the senators are asking why the RCMP chose not to use the Alert Ready system to issue a warning about the gunman, who remained at large for 13 hours. The system sends alerts to radio and TV stations as well as cellphones and other electronic devices. The police posted warnings on Twitter instead.

There are also questions about the perpetrator's firearms, threat assessments and previous warnings about his history of domestic violence.

"We strongly believe that the inquiry must address the social and public safety issues which are related to this tragedy, and not just focus on the details of how the RCMP responded to the events as they unfolded," the letter says.

"A feminist lens will be critical to the inquiry's success."

Nova Scotia Premier Stephen McNeil said Tuesday that discussions between the province and the federal government are ongoing, with the goal of ensuring "that all the players will be at the table."

The association that represents RCMP members issued its own statement, saying any type of federal-provincial inquiry should have a broad scope.

"When a tragedy like this occurs, it's short-sighted and insufficient to only look at the hours requiring an urgent police response," said Brian Sauve, president of the National Police Federation.

The federation, which represents 20,000 RCMP members, offered its own list of questions, including what other interactions the shooter had with federal or provincial agencies, whether he went through any previous psychiatric assessments and how his history of domestic abuse was addressed "by the courts or government agencies."

Police have confirmed the gunman -- disguised as a Mountie and driving a replica RCMP vehicle -- was armed with two semi-automatic handguns and two semi-automatic rifles when he killed 13 people in Portapique, N.S., on April 18 and another nine people the following day in several other communities in northern and central Nova Scotia.

His victims included an RCMP officer, two nurses, two correctional officers, a family of three, a teacher and some of his neighbours in Portapique.

After Gabriel Wortman spent the better part of 13 hours killing people he knew and others he didn't, a Mountie fatally shot the 51-year-old denturist at a gas station in Enfield, N.S., about 90 kilometres south of Portapique, on the morning of April 19.

There have been numerous calls for a public inquiry to investigate how police handled one of the worst mass shootings in Canadian history, including pleas from relatives of victims, politicians and more than 30 professors at Dalhousie University in Halifax.

This report by The Canadian Press was first published June 9, 2020.