RALEIGH, N.C. — A federal judge has tossed a lawsuit that blamed the security company formerly known as Blackwater for the deaths of four contractors killed in a grisly 2004 ambush on the streets of Iraq.

U.S. District Judge James C. Fox said court-ordered arbitration fell apart because neither side was paying the costs of that process, so he decided to shut the case nearly seven years after the killings. Katy Helvenston, the mother of contractor Scott Helvenston, said Tuesday the families couldn’t afford the costs, and she fears the case is over. The lawsuit was filed about a year after the men’s deaths.

“It’s pretty much destroyed my life,” Helvenston said. “I haven’t known one moment of joy since Scotty was slaughtered. I think the worst part is the betrayal from my country. I feel so betrayed.”

Insurgents killed the four contractors, then mutilated the bodies, dragged the charred remains through the streets and hung two of the corpses from a bridge.

Images from the scene were relayed around the world, and the event triggered a massive U.S. military siege known as the Battle of Fallujah.

Survivors of the contractors contend Blackwater failed to prepare the men for their mission and didn’t provide them with appropriate equipment, such as a map. Helvenston, Jerry Zovko, Wesley Batalona and Michael Teague were sent in Mitsubishi SUVs to guard a supply convoy. Their survivors argued they should have been given armored vehicles.

A congressional investigation concurred with that view, calling Blackwater an “unprepared and disorderly” organization on the day of the ambush.

Blackwater, however, argued that the men were betrayed by the Iraqi Civil Defense Corps and targeted in a well-planned ambush.

The company said the result of the ambush likely would have been the same even if they had stronger weapons, armored vehicles, maps or even more men.