WASHINGTON —  In the terror-conscious post-Sept. 11 world, DynCorp (search), the employer of the three security guards killed in the Mideast bombing Wednesday, has become the 10th-largest contractor of the U.S. government.

With more than 23,000 employees, DynCorp's duties are as varied as maintaining military aircraft in the Middle East and furnishing international police monitors in Bosnia (search) and East Timor (search).

In Iraq, DynCorp has a $50 million State Department contract to send up to 1,000 former police officers to train Iraqi police and advise the occupation administration on reorganizing the country's law enforcement agencies, according to the research firm Hoover's.

DynCorp employees also help guard Afghanistan's leader.

And a DynCorp subcontractor was killed last month when the U.S. plane he piloted was shot down over Colombia, apparently by anti-government rebels.

DynCorp's federal contracts in 2002 were just over $2.1 billion, up $700 million from the previous year.

Its employees took U.S. military equipment to the Middle East before the war against Iraq. The company also produces smallpox and anthrax vaccines for the war against terror.

Information technology is the other side of DynCorp's business. It networks all U.S. embassies abroad. It also built a 29,000-terminal computer network for the FBI.

All of this has made the Reston, Va.-based company highly attractive from a business standpoint. In March, DynCorp was purchased for $950 million by El Segundo, Calif.-based Computer Sciences Corp. (search) 

A U.S. official, speaking on condition of anonymity, described DynCorp's work in Israel preceding Wednesday's fatal bombing attack.

As violence has flared between Palestinians and Israelis in recent months, contract security personnel from the company have helped to guard the armored-car convoys that carry U.S. diplomats into the West Bank and Gaza, said the official.

Typically, such a convoy — whether for routine daily business or for peace-monitoring missions — would consist of three or four armored vehicles containing one armed State Department diplomatic security official, plus several other contract security people from DynCorp, in addition to the diplomats, the official said.