Brig.-Gen. Chris Davis said Canadian soldiers 'reacted appropriately' in the heat of battle. (CBC)

A Canadian general investigating the killing of a Canadian soldier in a possible accidental fire incident in Afghanistan says the decision to send the men into combat was the correct one.

Pte. Robert Costall was killed on March 29 during a night battle with Taliban insurgents. His unit had been sent to reinforce the remote Afghan base in Helmand province, about 110 kilometres from Kandahar. An American medic also died in the battle and three coalition soldiers were injured.

Brig.-Gen. Chris Davis was sent to Kandahar by Canadian military officials to determine whether, in the confusion of battle, Costall was killed by a bullet from the gun of a coalition soldier.

Davis said the battle was complicated because the pitch-black night sky may have been too dark for night-vision goggles to work.


Pte. Robert Costall was killed on March 29 during a night battle with Taliban insurgents. (DND/Canadian Press)

"What I can tell you is that it was extremely dark – what's called in the military two per cent illumination – very difficult for night-observation devices to work," said Davis.

There were "numerous players" in the battle, he added, including a convoy that arrived after "many, many hours of contact with insurgent forces."

"So it's very complex," he said.

Until now, the military has kept the investigation under tight wraps.

It is known that when the outpost came under attack by about 100 Taliban fighters, it was being manned by soldiers from the Afghan National Army and about a dozen American military advisers.

After receiving a call for reinforcements, the Canadian commander on duty in Kandahar dispatched a 38-man Canadian Quick Reaction Force.

That, said Davis, was the correct decision.

"Our soldiers were well prepared to go into that particular action and from what I've learned so far, reacted appropriately in the circumstance," he said.

Davis's mandate is to investigate the entire chain of events to determine if any mistakes were made and offer suggestions on how to correct them.

Davis said he is about one-third of the way through his investigation and expects to be finished no later than mid-June. The U.S. and Afghanistan are also conducting probes into the incident.