MONTPELIER, Vt. — A U.S. Army investigator has recommended that no charges be filed against the U.S. Special Forces machine-gunner who killed Canadian Private Robert Costall and an American soldier in Afghanistan last year.

The recommendation is in documents released by the army about the friendly-fire deaths of Costall and Vermont National Guard 1st Sgt. John Thomas Stone.

A report written by a U.S. Army officer whose name was blacked out says their deaths, while regrettable, are "understandable in the context of this firefight.''

The officer says Costall and 37 other Canadian soldiers were sent to reinforce Forward Operating Base Robinson for an expected attack on March 28, 2006.

The report, released to The Associated Press, says an "inaccurate target identification'' that night by the unidentified gunner caused him to fire at the rooftop position where Stone and other soldiers were crouched behind a wall, fighting off an attack by Taliban forces.

Costall, 22, was born in Thunder Bay, Ontario, and grew up in Gibsons, B.C.