Dr. David Morgan testified at a coroner's inquest into Matters' death on Thursday that he met the former soldier and peacekeeper in the Prince George Correctional Centre to conduct a clinical risk assessment in December 2010.
Matters was nearing the end of a 56-day incarceration after he was refused bail following a conviction for sending a threatening email to the head of the RCMP Public Complaints Commission.
"Thank you for not thinking that I am a serial killer," the 40-year-old former soldier wrote in the lengthy letter, parts of which were read out in court by a lawyer for the Matters family.
"Fact is, I cannot fully explain my state of mind when I made the decision to click send. I've been told it's one thing to write bad thoughts, it's another to send them. Could it have been a brief ... moment that caused me to click? I don't know."
"I am sorry for the alarming, disturbing words I sent, and (the) worry those words may have caused," Matters wrote, adding that he'd sent an apology to the commission, through his lawyer.
The conviction was one of a number of run-ins that Matters had with RCMP, beginning in New Brunswick, where he was based at CFB Gagetown. Matters said a dispute erupted with a local force member who was the ex-boyfriend of his best friend's wife.
Things escalated until, according to Matters, RCMP officers broke into his home one night at gunpoint on a purported "wellness check" because he hadn't responded to earlier calls. He filed a complaint about the incident to the RCMP watchdog, which found the complaint was not substantiated.
After leaving the military with an honourable discharge in 2009 and returning to Prince George, Matters was charged and later acquitted of assaulting his brother, Trevor, and investigated for sending threatening emails to his former therapist in New Brunswick.
The coroner's jury has heard that the threats issued in emails ranged from shooting, to cutting a person's throat. The perceived offences ranged from harassment and assault by RCMP officers, to an unjustified $30 parking ticket.
Morgan testified that he met Matters in December 2010, shortly after he'd ended a 35-day hunger strike in protest of being refused bail.
In his letter, he complains of spending 56 days behind bars, over Christmas.
"I have never hurt anyone — exception, rugby field when I was 14 years old," he wrote.
"One guy told me that he assaulted his wife, assaulted a police officer and other threats, and he got bail. Why am I seemingly being treated different?"
Matters said the Crown lawyer presented "slander and lies and exaggeration" in court. Matters was later charged with threatening the lawyer.
"These are the words of a man who after serving his country in Bosnia, coming home physically and mentally damaged, was acknowledging that he had problems and recognizing and reaching out for help with those problems, wasn't it?" asked Cameron Ward, the lawyer for the Matters family.
"Yes, sir," Morgan replied.
The letter arrived on Jan. 6, 2011 — after Morgan had prepared his assessment for the court. Nonetheless, based on the interview in jail, Morgan said he did not feel the former soldier posed a threat to the public.
His sentencing recommendation to the judge the year before Matters was fatally shot said he was not a high risk for violence.
Matters, admittedly, made "fairly dramatic threats," Morgan testified.
But "I did not consider that he was a grave and immediate risk. In fact, this was a man who had never committed a violent offence."
Matters — who was being treated for post-traumatic stress disorder — was shot on Sept. 10, 2012, by a member of an RCMP emergency response team sent to arrest him for assaulting his brother.
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