Security contractors were heckled, humiliated and physically abused by U.S. Marines in Iraq while jailed for 72 hours with insurgents, one of the detainees said Friday.

"It was disbelief the whole time. I couldn't believe what was happening," said Matt Raiche, 34, a former Marine who was one of 16 American and three Iraqi contractors detained at Camp Fallujah last month.

"I just found it crazy that we were being held with terrorists, that we were put in the same facility with them," he said in an interview at his lawyer's office. "They were calling us a rogue mercenary team."

Defense officials said Thursday that the security guards for Charlotte-based Zapata Engineering were detained for three days after they fired from trucks and SUVs on Iraqi civilian cars and U.S. forces in Fallujah, 40 miles west of Baghdad.

The military has denied that the contractors were abused. No charges have been filed against the contractors, who the military said were separated from suspected insurgents.

Company President Manuel Zapata said the only shot fired by his workers was a warning blast after they noticed a vehicle following them.

Raiche, of Dayton, Nev., said the contractors were stopped and taken into custody on May 28. He said a Marine told him that shots had been fired, and Raiche told him, "It wasn't us."

Raiche said several of the contractors were interrogated before they were released June 1 with no official explanation for their detention.

Raiche said guards intimidated the detainees with dogs, made them strip and told them to wear towels over their heads when they went to the restroom so insurgents in the facility would not recognize and harm them, Raiche said.

One of his colleagues was slammed to the ground by a guard, he said.

When Raiche first arrived at the facility, he said, a guard ordered him to the ground and put a knee in his back. He said he heard one Marine say, "How does it feel now, making that big contractor money?"

Raiche said the Marines handcuffed them with "zip lock ties." When the detainees complained that the restraints were so tight they were losing circulation in their hands, they were cursed at and told to shut up, Raiche said.

Raiche returned to Reno on Thursday night. He said he had been in Iraq for about two years before returning to Nevada earlier this spring, then headed back to Iraq on May 2.

About 20,000 Americans, many of them former military personnel, are believed to be working in Iraq for contractors. More than 200 private workers have died in Iraq.

Zapata Engineering contracts frequently with the Defense Department, and Zapata said he is waiting for completion of the investigation before he draws conclusions about how the military treated his workers.