On a recent morning here, military policemen marched 50 handcuffed men off a convoy that had just arrived from Tikrit, Mr. Hussein's hometown. Old and young, the detainees wore thin shirts or robes. Some were barefoot.

A sign on a concrete blast wall read, "No Parking: Detainee Drop Off Zone." Guards stood watch in towers along walls laced with razor wire. The detainees huddled quietly on the ground outside a squat building where they would be processed. Soon they would be asked to put on orange jumpsuits.

Death happens:

It was an incident at Camp Bucca on Jan. 31 that most recently exposed the potential hazards of the detainee system: Four detainees were killed and six wounded when guards fired shots to quell a well-organized uprising. The guards had replaced their nonlethal weapons with lethal ones after realizing that detainees had armed themselves with slingshots that could hurl stones for long distances. Since then, the military has bought guns that fire "plasticized projectiles" at a greater range, Colonel Johnson said.

Members of the military police say they are overworked.

Of the company's three platoons, one was guarding the 42nd Infantry Division's prison in Tikrit, another was assigned to protect the division's generals, and the third transported detainees.

In the three weeks after company arrived in Iraq on Feb. 1, the Third Platoon made 25 convoy runs all across the hostile Sunni Triangle, with a dozen of those to Abu Ghraib.

"We've got just enough people to do this" said Specialist Chris DiModica, 23, the driver of the command Humvee. "If anyone gets sick, that's it."