GUYSBOROUGH, N.S -- Lionel Desmond's deteriorating mental health in the months before the former soldier killed three family members and himself was at the centre of a fatality inquiry Monday as it completed its first phase after five weeks of hearings.

The Nova Scotia provincial court judge leading the inquiry, Warren Zimmer, made a point of asking the province's chief firearms officer if it was possible for his office to periodically check on firearms licence holders if they had a history of mental illness.

Zimmer suggested it might be a good idea to make sure their mental health status had not changed.

John Parkin told the inquiry that once a possession and acquisition licence is approved, it remains valid for five years, unless the Provincial Firearms Office has a reason to place the licence under review.

"I'm not sure what the mechanics of that would look like," Parkin told Zimmer. "I don't know if that's technologically possible or feasible."

Parkin also said his office would be reluctant to impose a policy of mental status checks because of potential legal concerns.

"We would need opinions with more expertise than my own on that one," he told the inquiry.

The inquiry has heard that Desmond was diagnosed with post-traumatic stress disorder in 2011 after he served in a combat role in Afghanistan in 2007.

When he was medically discharged from the military in June 2015, the Department of Veterans Affairs was aware Desmond was suffering from severe PTSD, major depression and a possible traumatic brain injury that required further assessment.

Desmond's firearms licence was suspended in December 2015 after his wife Shanna told RCMP in Oromocto, N.B., she had received texts indicating her husband was preparing to kill himself with a rifle. That was on Nov. 27, 2015.

The former infantryman was arrested under the provincial Mental Health Act, his weapons were confiscated and his firearms licence was suspended pending a written medical assessment.

However, his licence was reinstated and his firearms were returned in May 2016 after a doctor in New Brunswick signed a medical assessment that declared Desmond could get his licence back because he was "non-suicidal and stable."

It was around this time that Veterans Affairs recommended Desmond for a specialized residential treatment program at Ste. Anne's Hospital in Montreal, which he attended between June and August of 2016.

The inquiry heard that doctors at the hospital were concerned because Desmond left the program early, seemed to gain little from treatment and was ill-prepared to deal with civilian life as he headed home to eastern Nova Scotia.

More importantly, testimony and documents presented to the inquiry confirmed Desmond received no actual therapeutic treatment in the four months before the killings on Jan. 3, 2017, which prompted Zimmer to agree with a psychiatrist in Antigonish, N.S., who said Desmond had "fallen through the cracks."

The judge also noted that provincial and federal officials seemed to be operating in "silos" that prevented them from sharing key information.

For example, firearms and health-care officials in Nova Scotia and New Brunswick testified they were unaware of the extent of Desmond's mental illness because they did not have access to his federal files.

Among other things, the inquiry is trying to determine whether the Desmond family had access to services to help with mental health and domestic violence, and whether the health-care professionals who dealt with Desmond were trained to recognize mental health and domestic violence issues.

The first phase of the inquiry heard mainly from police, provincial health-care providers and firearms officials.

The second phase, which is slated to begin in May, will mark a big shift for the inquiry as key testimony is expected from various federal officials, including staff with Veterans Affairs Canada.

This report by The Canadian Press was first published March 2, 2020.