SHILO, Man. -- The fate of a former Canadian soldier who led a deadly training exercise in Afghanistan is in the hands of a military judge, who must decide whether Paul Ravensdale should be put behind bars or simply demoted.

Ravensdale's lawyer told a sentencing hearing Thursday that the now-retired warrant officer was involved in a "tragic accident" and has suffered enough.

"We do not feel that our client is at risk to reoffend," Lt.-Cmdr. Patrice Desbiens told the court martial.

"The sentence must allow our client to go on with his life."

The military prosecutor in the case has asked for a four-year prison sentence. Maj. Tony Tamburro said in his closing submissions earlier this week that Ravensdale ignored safety rules and he added that a strong message must be sent to other soldiers that safety is a must.

Ravensdale was leading a test of C-19 anti-personnel mines at a weapons range near Kandahar city on Feb 12, 2010 when one apparently misfired, sending hundreds of steel ball bearings backward instead of forward. The projectiles killed Cpl. Josh Baker, 24, and injured four other soldiers.

Ravensdale was convicted on four charges including breach of duty causing death for ignoring safety rules that require soldiers to be at least 100 metres behind a C-19 mine unless they are shielded by a dugout, a vehicle or some other barrier. Video played at the court martial showed some soldiers standing much closer than 100 metres and with no protection.

The weapons test had been planned for a week and the court martial was told Ravensdale never consulted the Canadian Forces' weapons training guide or the operating instructions for the C-19s.

But Desbiens said Ravensdale was the victim of an incompetent superior who, contrary to military rules, made Ravensdale both the officer in charge of the weapons test and the safety officer for the weapons range that day. The tasks are supposed to be given to separate people.

"He was basically given a task to do that day that was impossible to do."

Desbiens asked that Ravensdale be given a reduction in rank and a severe reprimand. He pointed to the fact that Ravensdale was soon afterward diagnosed with severe depression and post-traumatic stress disorder.

He also said imprisonment would prevent Ravensdale from continuing his current treatment. Ravensdale is very anxious when in public settings and has a hard time trusting strangers, a psychologist testified earlier this week. As part of his therapy, he goes to shopping centres and other venues -- something that would be hard to do while behind bars, Desbiens said.

The military judge hearing the case, Col. Mario Dutil, said Thursday he will deliver his decision March 18.

Two of Ravensdale's superiors have already been convicted for their roles in the accident.

Maj. Darryl Watts was demoted two ranks to lieutenant and given a severe reprimand on charges of negligence and unlawfully causing bodily harm.

Maj. Christopher Lunney was demoted one rank to captain and given a severe reprimand after pleading guilty to negligent performance of duty.