MONTREAL — Canada said on Tuesday it was launching a public inquiry into the country's deadliest mass shooting to shed light on the tragedy and respond to demands for transparency by victims' families.

The Nova Scotia arson and shooting rampage that killed 22 people April 18-19 ended with police gunning down the shooter after a 13-hour manhunt.

Minister of Public Safety and Emergency Preparedness Bill Blair said that Canadians "deserve answers to how such a tragedy could occur" as he announced the full public inquiry.

"We have heard calls from families, survivors, advocates, and Nova Scotia Members of Parliament for more transparency," he said in a statement.

The killing spree was carried out by a male dental health care professional identified as Gabriel Wortman, 51. Authorities said he was wearing a police uniform, driving a mock police car and had several guns with him, including at least one assault-style weapon.

Police gunned down Wortman on April 19 after a 150 kilometre manhunt, during which time the gunman shot dead 22 people, including a Royal Canadian Mounted Police (RCMP) constable.

The government announced last week it was launching an independent probe to determine why police took more than 12 hours to stop the shooter.

But in recent days there have been several demonstrations in Nova Scotia, supported by 37 senators, calling on authorities to go further and launch a public inquiry.

A public inquiry will provide investigators with additional powers, including summoning witnesses and compelling them to appear for testimony or provide documents.

In addition to the shooting, Wortman had a long criminal history, according to reports by a media consortium that had access to federal police documents.

For several years Wortman had been dealing in weapons and drugs brought over from the US state of Maine that he hid in secret compartments at several of his properties.

Canadian police were criticized for using Twitter to warn the public that an armed suspect was on the loose, rather than issuing a formal emergency alert. — AFP