OTTAWA - The fate of the American pilot who mistakenly shot up Canadian troops last fall, killing one and wounding 30, will be decided by his commanding officer, the U.S. Air Force said Monday.

An investigation by American authorities has concluded that the pilot, who has yet to be identified, was responsible for the incident that killed Pte. Mark Anthony Graham, a former Olympic athlete, on Sept. 4, 2006.

The inquiry found by "clear and convincing evidence" that the cause of the early morning incident was the "misidentification of a friendly position by the mishap pilot", said a censored version the U.S. investigation released Monday.

It states that the pilot of the A-10A Thunderbolt II sprayed 180 rounds of 30 millimetre high-explosive bullets from the aircraft's Gatling gun, aiming at a garbage fire he thought was the smoky residue of a bomb he'd just dropped.

Members of Charles Company 1st Battalion Royal Canadian Regiment had camped overnight at the base of Ma'sum Ghar, a rocky outcrop about 40 kilometres west of Kandahar, and were preparing to resume fighting when the attack jet swooped in.

The pilot, who had removed his night vision goggles, pulled the trigger even though the rising sun and weather conditions prevented him from seeing the ground at all, U.S. investigators found.

"The mishap pilot was at a range and altitude from where he could see neither personnel nor friendly vehicles in the mishap area," said the American report's executive summary.

The findings of the U.S. investigation are similar to the results of a Canadian military board of inquiry, which was released late Friday night.

Maj. John Elolf, a spokesman for the U.S. Air Force, says now that the investigation is complete, the commander of the 81st Fighter Squadron must now decide whether there is enough evidence to charge the pilot with negligence.

"It's all up to him; it's all up to the commander on what he wants to do," Elolf said in an interview from Shaw Air Force Base, near Sumter, N.C.

The pilot had 60 combat missions in Afghanistan to his credit and was considered "highly experienced and competent," according to the separate Canadian investigation. He has since ended his tour and returned with his unit to Spangdahlem Air Base in Germany.

Elolf could give no timeline on when a decision will be made about possible charges and also would not identify the pilot for security and privacy reasons.

The deadly mistake came at the height of Operation Medusa, the Canadian-led offensive to sweep the Taliban out of the Panjwaii district, where they had been massing for their offensive to retake Kandahar city.

It is the third time since Canada landed in Afghanistan following the ouster of the Taliban in 2001 that troops have died as a result of U.S. friendly fire.

In April 2002, four soldiers were killed and eight wounded when an American F-16 mistakenly dropped a bomb on their training exercise. Last spring, Pte. Robert Costall and a U.S. medic were accidentally machine gunned to death by an American special forces soldier at a remote firebase in Sangin.

In the Ma'sum Ghar attack, Charles Company was decimated by the attack, which came less than 24 hours after four other Canadian soldiers - Sgt. Shane Stachnik, Warrant Officer Frank Robert Mellish, Pte. William Cushley and Warrant Officer Richard Francis Nolan - had been killed in the fighting.

A Canadian lessons-learned report - obtained by The Canadian Press last spring - suggested that pilot fatigue might also have been a factor as four U.S. aircraft had been flying all night, bombing and strafing Taliban positions in the area.

Two of the opposition parties took a shots at the Conservative government Monday over the timing of the release of the Canadian investigation.

New Democrat defence critic Dawn Black said putting the report out after 5 p.m. on a Friday, the same day that the trial of media baron Conrad Black comes to end, is a guaranteee that the findings will not register with the public.

"The government is worried about the loss of support by the Canadian public for this mission," said Black, in a telephone interview from her B.C. home "They're looking at ways to keep stories off the front pages, especially issues of deaths by friendly fire. That's wrong. I think Canadians need to know the full details of this."

Liberal defence critic Denis Coderre said burying the report also gives the government the opportunity to avoid troubling questions that were raised about the inadequate training of Canadian soldiers whose responsibility it is to call in air strikes.

Maj. Richard Perreault, a spokesman for the Canadian Forces, said Monday that there was no intention by the military to downplay the report.

Release of the 118-page document was held up as the military censored parts of it for national security reasons.