Relatives of a Nova Scotia soldier killed in Afghanistan last year are pressing forward with their lawsuit against the U.S. Air Force.

Four Canadian soldiers were killed and eight others wounded when American F-16 pilots mistakenly dropped a bomb on troops doing live-fire exercises.

A U.S. military investigator recommended on Thursday that the two pilots not face a court-martial, despite having enough evidence to try them on charges of involuntary manslaughter, aggravated assault and dereliction of duty.

Dick Murtha, the lawyer for Doreen Coolen, the mother of friendly-fire victim Private Richard Green, said she was upset by the recommendation of the American military investigator.

"I spoke with Mrs. Coolen and Mrs. Coolen cried," said Murtha, adding that the military investigator's recommendation has fueled the family's determination to seek answers and compensation.

"Mrs. Coolen had made a promise to her son that she would not allow his death to go in vain," said Murtha. "We're not going to sit and let this happen."

Private Green's fiance, Miranda Boutilier, agrees the pilots made a terrible, tragic mistake and should be punished. But she doesn't want any part in the lawsuit.

"The compensation is blood money," she said. "The money, if there is any, would not be there if it wasn't for Ricky's death and I don't want any money."

Murtha said the money isn't as important as the need to make sure nothing like this ever happens again, an important point as U.S.-led forces continue to fight in Iraq.