Civilian contractors such as Thomas Jaichner are not part of the U.S. armed forces, but they put their lives at risk in some of the most deadly parts of Iraq.
In fact, one researcher said contractors frequently face equal or greater dangers than frontline soldiers.
"There are situations when they are more at risk," said Deborah Avant, associate professor of political science and international affairs at George Washington University, who is writing a book on the trend toward the privatization of military tasks.
Although private security forces often perform many of the same functions as U.S. troops, Avant said, they are not governed by military rules mandating the amount of men and firepower they take along for tasks such as convoy protection.
"With soldiers, there are concrete rules and standard operation procedures that spell out that there needs to be this many Humvees or tanks with this many trucks," Avant said. "In the private security realm, you don't have that. It's often at their own discretion."
It is unclear how many private security employees are in Iraq. The Department of Defense declined to release a number, but Avant said the Iraqi Department of Interior has counted about 50,000.
According to the casualty listings on the Web site http://www.icasualties.com/, 234 civilian employees have died in Iraq since the start of hostilities in Iraq, including 85 Americans.
There have been 1,612 U.S. military casualties as of May 13, according to the Defense Department.
Blackwater Security Consulting, the security contractor that was employing Jaichner, has lost 19 employees in Iraq, according to a company spokesman.
The company, which is headquartered in Moyock, N.C., received worldwide attention when four of its security consultants were killed and their corpses mutilated by a mob in Fallujah in March.
More recently, six Blackwater employees died April 21 when Iraqi insurgents shot down a Bulgarian helicopter transporting them.
Avant said private security firms began forming at the end of the Cold War because of cutbacks to the U.S. military. She said demand for private firms in Iraq is high because of the degree of lawlessness in the country.
"Basically, anyone who wants to go anywhere needs armed escorts, and there's not enough soldiers to go around," Avant said.
She said most civilian security employees are retired military or police who are often paid two to four times the salaries given to soldiers to work for a private firm.