A private security firm Friday identified its seven guards who were killed on a single day this week in Iraq, including a former sergeant whose stepfather said he died "doing what he loved to do."

Six Blackwater Security Consulting (search) guards responsible for protecting U.S. diplomats were killed Thursday when their helicopter was shot down as it headed from Baghdad to Tikrit for a security detail, said company spokesman Chris Bertelli.

A seventh Blackwater guard was killed near Ramadi (search) when a bomb exploded next to one of the company's armored personnel carriers.

It was the bloodiest day of the Iraq conflict for the company, which is employed by the U.S. government for tasks ranging from the personal security for diplomats to protection for aid convoys.

William Hawkins said his stepson, Steve McGovern, had been a sergeant in the National Guard (search) with the 20th Special Forces Group in Louisville before leaving in February to work for Blackwater. He had just started his second mission in Iraq.

"He was just doing what he loved to do," Hawkins said.

Jason Obert left the sheriff's department in El Paso County, Colorado, in February to earn extra money working in Iraq for Blackwater, Sheriff Terry Maketa said. He had been in Iraq since last month.

"He was always willing to help out his fellow workers with anything, a real team player," Maketa said. "It's a shame to have something like this happen."

Moyock-based Blackwater identified those killed aboard the helicopter as Robert Jason Gore, 23, of Nevada, Iowa; Luke Adam Petrik, 24, of Conneaut, Ohio; Eric Smith, 31, of Waukesha, Wis.; David Patterson, 27, of Havelock; Obert, 29, of Fountain, Colo.; and McGovern, 24, of Lexington, Ky.

The guard killed near Ramadi was identified as Curtis Hundley, 42, of Kernersville.

The bodies of the seven were being transported back to the United States aboard military aircraft, Bertelli said.

A total of 11 people died in the helicopter crash about 12 miles north of Baghdad, including three Bulgarian crew members and a pair of security guards from Fiji.

At least 18 Blackwater guards have died in Iraq, including four whose slaying and mutilation in Fallujah were captured in graphic news photographs in March 2004. Two of the corpses were hung from a bridge, triggering a bloody three-week siege of the Sunni Muslim city west of Baghdad.

Blackwater is one of many private security contractors working in Iraq, where thousands of civilians with other companies feed U.S. troops, fuel vehicles and train Iraqi police.