SHILO, Man. -- A retired Manitoba soldier faces the possibility of life in prison after being convicted of four charges stemming from a deadly training accident in Afghanistan.

A court martial panel on Thursday found retired warrant officer Paul Ravensdale guilty of breach of duty causing death, breach of duty causing bodily harm, unlawfully causing bodily harm and negligent performance of military duty.

The five-member panel -- akin to a jury in a civilian trial -- found Ravensdale not guilty of manslaughter and a second count of negligent performance of military duty.

"What I hope (the verdict) would do is cause others to think twice and to reflect on the nature of what they're doing ... and to take further steps to keep their soldiers safe," prosecutor Maj. Tony Tamburro said after the hearing.

Ravensdale was leading a test of C-19 anti-personnel mines on a weapons range near Kandahar city in February 2010 when one mine misfired and sent hundreds of steel ball bearings in the wrong direction. Instead of fanning out forwards, the ball bearings shot backward, directly toward soldiers who were watching.

Some of the projectiles hit and killed Cpl. Josh Baker. Four other soldiers were injured.

The panel had begun deliberating Wednesday morning. The verdict came with little advance notice and some of Ravensdale's supporters did not make it to the hearing in time to hear the panel's decision.

Ravensdale appeared to take in a deep breath as the verdict was read, but showed little emotion.

The prosecution had argued that Ravensdale ignored safety rules and allowed soldiers to stand too close to the mine, but the defence said Ravensdale was simply following plans approved by his superiors.

The operating manual for the mines, as well as Canadian Forces training safety rules, require people to be 100 metres behind C-19s unless they are shielded. Video played at the court martial showed some soldiers much closer than that and with nothing protecting them.

"There was definitely confusion about what the safety radius was and ... that was because the soldiers were never told," Tamburro said Thursday.

Ravensdale's lawyer, Maj. Philippe-Luc Boutin, said during closing arguments that no one could have predicted the mine would act the way it did. He said the 100-metre limit is designed to protect people from minor injuries that might be caused by stones or other debris being kicked up by the blast.

Boutin also pointed to testimony from witnesses who said Ravensdale had told them to stay behind a row of light armoured vehicles.

The court martial heard that some stood between vehicles or on top of them and Ravensdale gave the order to fire anyway.

Boutin said Ravensdale was disappointed with the verdict.

"We expected another outcome, but this is what the panel has decided and we'll have to live with it."

The conviction on breach of duty causing death carries a maximum sentence of life in prison, although both the prosecution and the defence said Thursday they had not yet decided what sentence they will seek at a hearing set for March 4.

"The sentence in the Maj. Watts trial is going to provide us with a good indication as to where we should go," Boutin said.

Maj. Darryl Watts, one of Ravensdale's superiors, is awaiting sentencing on charges of negligence and unlawfully causing bodily harm.

Another superior, Maj. Christopher Lunney, was recently demoted to captain and given a severe reprimand after pleading guilty to negligent performance of duty.

Ravensdale did not testify at his court martial and his lawyer did not call any witnesses. In an interview with a military investigator days after the accident, Ravensdale said he had no idea what went wrong and that "all hell broke loose."