HALIFAX -- The joint public inquiry in response to the April mass shooting in Nova Scotia has announced a mandate that includes a probe of the RCMP response as well as the role of gender-based violence in the tragedy.

The federal and Nova Scotia governments announced in July their intent to establish the inquiry to determine what happened and make recommendations to help prevent similar events in the future.

A lone gunman killed 22 people on April 18-19 during a 13-hour rampage that spanned several communities in northern and central Nova Scotia.

The killer was shot dead by RCMP officers at a gas station in Enfield, N.S.

Thursday's announcement says the terms of reference are complete, a third commissioner has been chosen and the commission is set to begin its work.

A release says Kim Stanton will join chief commissioner Michael MacDonald, a retired chief justice of the Nova Scotia Supreme Court, and Leanne Fitch, a former chief of police in Fredericton.

Stanton is a lawyer and the former legal director of the Women's Legal Education and Action Fund.

They are to submit two reports on their findings, lessons learned and recommendations, with an interim report by May 1, 2022 and a final report by Nov. 1, 2022.

Under the federal Inquiries Act and the Nova Scotia Public Inquiries Act, the commissioners have the power to call witnesses under oath and require them to provide documents or other items that the commissioners consider necessary to carry out a full investigation.

Two orders-in-council were released outlining the commissioners' terms of reference.

They direct the commissioners to inquire and make findings into the causes, context and circumstances giving rise to the tragedy, the responses of police, and the steps taken to inform, support and engage victims, families and affected citizens.

The commissioners are tasked with looking at the "role of gender-based and intimate partner violence" and "access to firearms."

In addition, the mandate calls for examination of the gunman's "interactions with police, including any specific relationship between the perpetrator and the RCMP and between the perpetrator and social services, including mental health services," prior to the event.

The commissioners are to look at police actions, including operational tactics, response, decision-making and supervision, along with communications with the public during and after the event.

They're also to consider communications between and within the RCMP, Canada Border Services Agency, Criminal Intelligence Service Nova Scotia, the Canadian Firearms Program and the Alert Ready Program.

The terms of reference call for an examination of police policies in terms of gender-based and intimate partner violence and police training in active shooter incidents.

The shooter used a replica police vehicle during his rampage and wore an RCMP uniform, and the commission is being called to look into policies on the disposal of police vehicles and any associated equipment, kit and clothing.

The commission is to be "guided by restorative principles in order to do no further harm," and a provision also notes it is to grant to the victims and families of the victims an opportunity for appropriate participation in the inquiry.

This report by The Canadian Press was first published Oct. 22, 2020.