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Soldiers stationed at CFB Wainwright fly the regimental flag of the 3rd Battalion Princess Patricia’s Canadian Light Infantry (PPCLI), in Wainwright, Alta., on Wednesday.Christopher Katsarov/The Canadian Press

A wildfire that killed four Canadian Forces soldiers at a military base in Wainwright, Alta., on Saturday started on the base’s automatic grenade launcher range, Brigadier-General Vanessa Hanrahan told reporters on Thursday.

Brig.-Gen. Hanrahan is the Canadian Forces Provost Marshal, the top solider in charge of Canada’s military police, which is conducting one of three concurrent investigations into the fire. The military is conducting its own board of inquiry, and Alberta’s Office of Chief Medical Examiner is also investigating.

At a press conference Thursday afternoon, Brig.-Gen. Hanrahan said her investigation shows the fire started at what’s called the “AGL” range, as part of routine training in that area.

The fire initially stayed within what is known as a “permanent danger area” of the range, which prevented firefighters from attacking it directly.

“It was therefore monitored throughout the day by both range control and the base fire hall,” Brig.-Gen. Hanrahan said.

The fire later spread to a different range in another part of the base and overran soldiers’ positions, but understanding how and why that happened will be a key focus of three ongoing investigations, she said.

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Four were killed and dozens were injured.

The four killed were identified as: Pte. Shaun Farrell, 23, of Prince Albert, Sask.; Pte. Aidan Goulding, 23, of North Vancouver; Pte. Hayden Lykkemark, 19, of Langley, B.C.; and Sgt. Morgan Wong, 26, of Edmonton.

Initially, 39 wounded went to various hospitals. As of Thursday, there were 27 people still in hospital, according to Major-General Wade Rutland.

“We are heartened that 12 soldiers are no longer hospitalized, although they will still continue to receive follow-up care,” Maj.-Gen Rutland said. “The soldiers remaining in hospital are in serious condition.”