GUYSBOROUGH, N.S. -- An Afghanistan war veteran shot his wife, daughter and mother from about one metre away before firing a bullet into his own forehead, a pathologist testified Thursday at a public inquiry.

Dr. Erik Mont, Nova Scotia's deputy chief medical examiner, provided expert evidence to the inquiry into the Lionel Desmond case in Guysborough, N.S., describing medical autopsies his office's team performed.

Mont also testified that the autopsy indicated Desmond -- who was suffering from PTSD after returning from Afghanistan in 2007 -- had signs of the antidepressant drug trazodone in his body, but he said he couldn't comment on whether it "affected his mental state."

The pathologist said Desmond's death after he shot himself with the military-style carbine he had purchased just hours earlier was "essentially instantaneous" due to massive injuries to the brain.

Mont said the extent of the head injury made it almost impossible to test for signs of the brain injury known as chronic traumatic encephalopathy, or CTE, in the former soldier's brain.

Adam Rodgers, the lawyer representing the estate of Lionel Desmond, noted links have been drawn in the United States between CTE and suicides in professional athletes, and asked if there is analysis being done in Nova Scotia to trace the extent of diagnoses of CTE in the province.

Mont said "very little" diagnosis of the brain injury is being carried out, and his office has not studied any links between CTE and suicides in younger men.

In a December 2016 Facebook posting, Desmond said he had hit his head on a light armoured vehicle and suffered back spasms after falling off a wall and had been told he had post-concussion disorder as well as PTSD.

He wrote in the posting he had "ADD/ADHD from thrashing my head," and doctors told him he should seek neurological help in Halifax.

The five-week inquiry is examining whether Desmond had access to mental health and domestic violence services -- and whether he should have been able to buy a gun on Jan. 3, 2017, the date of the killings in Upper Big Tracadie.

RCMP investigators have testified during the first week of hearings that the veteran had struggled to cope with daily life after returning from Afghanistan in 2007, and had conflicts with his spouse.

Mont said his team's autopsy of Shanna Desmond, the former soldier's spouse, showed two bullets lodged in her body after entering her chest and abdomen. Another bullet passed through her neck. The pathologist said Shanna died "within seconds," as a bullet cut through her spinal cord.

"It (the bullet) would sever any connection between the brain and the body," he said.

He said the death of Desmond's 10-year-old daughter Aaliyah occurred within "minutes" after a single shot entered through her jaw and into her chest. Desmond's mother, Brenda, also died in "minutes" after a single shot went through her back, shoulder and neck, then lodged in her body.

Mont said he couldn't be sure of the order in which the three were shot.

The autopsy of Lionel Desmond detected meta-chlorophenylpiperazine, or MCPP, a metabolite of the antidepressant drug trazodone, which is used to treat depression.

Stewart Hayne, the lawyer representing doctors who interacted with Desmond, asked about other drugs, including medicinal marijuana and quetiapine, an antipsychotic medicine.

Mont confirmed those drugs were not detected, and indicated Desmond hadn't taken marijuana within three days and "there was no detectable quetiapine" in his body at the time of his death.

The inquiry has heard that Dr. Paul Smith, a family physician who worked at Canadian Forces Base Gagetown in New Brunswick, was the man responsible for granting Desmond approval for a firearms licence, even though he was aware of the veteran's PTSD diagnosis.

The inquiry heard during Hayne's opening statement that Smith had prescribed medical marijuana for Desmond in July 2015 to help him cope with major depressive disorder and PTSD.

Three months later, Desmond told Smith the drug had helped reduce his anxiety and depression, while virtually eliminating his suicidal thoughts.

However, Hayne said Desmond had stopped using medical marijuana by February 2016, which is when Desmond asked Smith to sign off on a medical assessment form for a firearms licence.

Though Smith was aware that Desmond was experiencing marital problems, he "felt comfortable completing the form indicating that he had no concerns that Mr. Desmond posed a safety risk to himself or others," Hayne said.

The inquiry will resume on Feb. 3.

This report by The Canadian Press was first published Jan. 30, 2020.

-- By Michael Tutton in Halifax.