Friends remembered Scott Helvenston (searchas a dedicated athlete who was just as comfortable having fun with his children as he was helping Hollywood stars go through grueling training.

Helvenston, 38, was among four American civilian contractors killed in Iraq in an ambush on Wednesday. They were working for Blackwater Security Consulting (searchwhen their vehicle was hit by rocket-propelled grenades.

In images seen around the world, an angry mob dragged the men's bodies through the streets of downtown Fallujah and strung two of them from a bridge over the Euphrates River.

A statement on Blackwater's Web site said company officials were grieving for the deaths of the employees.

"Our tasks are dangerous, and while we feel sadness for our fallen colleagues, we also feel pride and satisfaction that we are making a difference for the people of Iraq," the statement said.

Two of the other victims have been identified as Jerko "Jerry" Zovko, 32; and Michael Teague, 38, of Clarksville, Tenn.

Helvenston had served 12 years in the U.S. Navy, and was a member of the elite Navy SEALs special forces before leaving the service for a career as a fitness instructor and Hollywood consultant.

He lived in Oceanside, south of Camp Pendleton Marine Corps Base (search), and worked as a trainer and stunt man on movies including "Face/Off" and "G.I. Jane," where he helped prepare star Demi Moore for her role as the first woman to join the SEALs. He also appeared on two reality series: "Man vs. Beast" and "Combat Missions."

A close friend, Garth Estadt, said Helvenston led a successful life, despite growing up in the foster care system.

"For him, everything was passionate," Estadt said Friday in a television interview. "If you have a couple friends like that, you're a rich man."

Mark Burnett (search), producer of "Combat Missions," said he'd met Helvenston during the 1993 Raid Gauloises, a precursor to the Eco-Challenge, and said he was upset to hear about the former SEAL's death.

"It makes it all seem so much closer," Burnett told The Associated Press in a phone interview. "It reminds me of 'Black Hawk Down."'

Friends in Oceanside were devastated by the news.

"He wasn't there to engage in any fighting, although he only told me so much about it," friend Anthony Elgindy told the San Diego Union-Tribune. "He was there to maintain the peace and protect the civilians who are there."

Neighbor Fred Atkinson said Helvenston was a devoted father to his children, Kyle and Kelsey, and often took them camping or surfing.

Helvenston had also founded a fitness company, Oceanside-based Amphibian Athletics, that promised to bring a Navy SEALs-style workout regimen to his customers.

His wife, Tricia, had also participated in the Raid Gauloises in years past and appeared in some of the company's workout videos.

It was not surprising that Helvenston had gone to Iraq to help his country after years out of the service, Burnett said.

"That's what, in a time of need, true American warriors like Scott would do," he said.