Canadian military officials said Tuesday they would not charge a U.S. Special Forces machine gunner in the friendly fire death of a Canadian soldier last year in Afghanistan.

An investigation into the March 2006 death of Canadian Pvt. Robert Costall and Vermont National Guard 1st Sgt. John Thomas Stone found that they were killed by gunfire from a U.S. soldier during an attack of "unprecedented intensity" by Taliban forces.

Four others were injured, including three Canadians, in the firefight.

In July, a U.S. army investigator recommended no charges be filed against the American machine-gunner.

Canadian Chief of Defense Staff General Rick Hillier said he was satisfied with the board's findings. New rules have been incorporated into the military's standard operating procedures to improve the safety of soldiers, he said.

The Canadian report blamed "incomplete coordination and control" among the forces, as well as poor situational awareness, for the death and injuries to the Canadians.

U.S. reports concluded that an inadequate base defense plan, fatigue, lack of communication from headquarters and significant supply problems at the base in southern Afghanistan contributed to the shootings.

In a statement, Costall's family said he should be remembered for what he lived for, rather than how he died