But just how much of a role the electric stun gun played in the 27-year-old's death was the subject of much contention Friday before a jury retired to deliberate what's been described by Ontario's top pathologist as an "index case."
"There's clearly controversy around this case...specifically around the cause and manner of Mr. Firman's death," presiding coroner William Lucas said in his charge to the jury.
"The circumstances of the death of Mr. Firman have raised some questions."
Firman, a man with schizophrenia, died in June 2010 after an encounter with Ontario Provincial Police in Collingwood, Ont. Ontario's police watchdog cleared the officers of any wrongdoing, but said the Taser's deployment caused Firman's death.
Lucas suggested there were two possible ways to characterize Firman's cause of death — "accidental," as Firman's family has suggested, or "undetermined," as Taser International has argued.
As he urged the jury to weigh all the evidence and testimony that has come before them, he warned the five-member panel not to resort to an "undetermined" cause of death as a matter of convenience.
"Finding a manner of death of "undetermined" should not be used simply as a means to avoid having to reach a conclusion which may be unpopular," he said.
The inquest, which has been sitting intermittently since April, has heard vastly different testimony from experts. Some have suggested that the use of a Taser on Firman was a key factor in his death. Others argued the stun gun had little to do with the fatality.
Firman's parents, who have maintained that their son would be alive if it hadn't been for the Taser, said they wanted his death to be a catalyst for change.
"I hope with all my heart that Aron's death will not be for nothing," father Marcus Firman said as he choked back tears. "My hope would be to come away from the inquest with a vision on how to go forward with dealing with mental illness."
Aron Firman was described by his father as a gentle, artistic and inquisitive man who was keenly aware of his "terrible illness." Both parents said their son's loss had left an aching void in their lives.
The lawyer for the Firman family suggested the jury deem Firman's death an accidental one in which the Taser was an important factor.
His argument was based largely on previous testimony from Dr. Michael Pollanen, Ontario's chief pathologist, who conducted Firman's autopsy and found the Taser was the "most immediate factor" in his death.
"If you find that the Taser was related in that death...the world will not end," lawyer Sunil Mathai told the jury.
"If you make that finding, you're not standing alone on that. You're standing with the chief pathologist of Ontario — a man recognized worldwide as a leader in pathology."
Mathai also assured the jury that Firman's family was not seeking an eradication of Tasers.
"The family takes the position that Tasers have proper place in policing," he said. "This is not a Spanish Inquisition into Tasers. We are not seeking to remove them."
Meanwhile, the lawyer representing Taser International has suggested Firman could have died from cardiac arrhythmia brought on by "excited delirium" — a condition sometimes cited as a cause of death in people using cocaine or those with severe mental illness.
David Neave urged the jury to label the cause of Firman's death as "undetermined."
"The preponderance of the evidence that is now before the jury is that the Taser played no role in his death," Neave told The Canadian Press outside the inquest.
"I don't think it's an index case...This case is not about Taser discharge. This case is quite frankly about the state of excited delirium that Mr. Firman was in and the medical conditions or medical changes that that syndrome causes."
The jury is now considering how it can characterize Firman's death and may put forward recommendations on what can be done to prevent similar deaths in the future. It is expected to return with a verdict next week.
The use of Tasers by police has come under increased scrutiny over the years, particularly in the high-profile death of Polish immigrant Robert Dziekanski, who died after he was Tasered several times during an altercation with RCMP officers at Vancouver's airport in 2007.
A public inquiry into Dziekanski's death has said multiple deployments of the Taser along with a physical altercation contributed to the circumstances that lead to Dziekanski's heart attack. The BC Coroners Service agreed with the conclusions of the inquiry.
Dziekanski's death led to a number of recommendations, which were implemented by all police officers working in British Columbia, including the RCMP. They included getting better training on Tasers, using the weapons only if there's a danger a suspect will cause bodily harm, and training officers in crisis management.
Firman's family made similar suggestions in 21 recommendations submitted to the jury on Friday.
They included asking the jury to recommend that Ontario Provincial Police provide annual, mandatory crisis intervention and resolution training, which would have input from mental health professionals and those with mental-health issues, and that the province appoint a co-ordinator for implementation of that training.
The family also wants the jury to recommend the OPP revise its use-of-force policy for conducted energy weapons so an officer is prohibited from using one unless satisfied that de-escalation or crisis intervention techniques haven't worked and no option involving less force will work to eliminate the risk of someone getting hurt.