Maj. Darryl Watts, 44, faces charges that include manslaughter, unlawfully causing bodily harm, breach of duty and negligent performance of duty.
Cmdr. Peter Lamont, the military judge overseeing the court martial in Calgary, delivered a two-hour charge to the five-member jury panel late Saturday afternoon.
"The time has come for you to make your finding," said Lamont.
"You have now heard all of the evidence. In every court martial there are two judges. I am one — you are the other," he said.
"You are the judges of the facts. You — not I — will determine the evidence in this case."
Cpl. Josh Baker, 24, died and four other soldiers were injured when a Claymore anti-personnel mine, packed with 700 steel balls, peppered their platoon on a training range near Kandahar city in February 2010.
The Crown argues that Watts, who was the platoon commander, turned a blind eye to safety standards and abdicated his duty as a leader during the exercise.
"Maj. Watts, being the platoon commander having ordered his platoon onto that range, is responsible for the conduct of the range," said senior prosecutor Maj. Tony Tamburro in an interview with reporters Saturday.
"He can delegate certain tasks to his subordinates but he still remains accountable for the way those tasks are performed."
The defence counters that Watts had no training on the Claymore, so he handed over responsibility for safety to his second-in-command, who was an expert on the weapon.
Cmdr. Lamont told the panel it had to be sure within a reasonable doubt that Watts was guilty of the charges he has been charged with and that every person charged with an offence is presumed to be innocent.
"You must find the accused innocent of the offence unless the prosecution proves it beyond a reasonable doubt," said Lamont.
The platoon, which was stationed at Camp Nathan Smith in Kandahar city, usually visited the Kan Kala firing range about once a month.
The day of the accident the range was divided into four training sections.
The first two tests of the anti-personnel mine went off without a hitch. But when the second firing occurred, the ball bearings fired backwards, hitting Baker and four others.
Videos of the accident show several soldiers, including Watts, standing around watching the tests. They were not inside armoured vehicles or standing behind them for cover, as set out in Canadian Forces safety guidelines.
Maj. Tamburro acknowledged that it was a difficult case to prosecute.
"Negligence cases are always somewhat difficult because we're not alleging crimes of intent here. No one has ever alleged that Maj. Watts intentionally harmed anyone or killed anyone," Tamburro said.
Cmdr. Lamont also warned the jury not to go beyond deciding the guilt or innocence of the accused.
"Punishment has no place in your discussion or in your decision," said Lamont.
"It is my job — not yours — to decide what kind of punishment is appropriate."
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