In a house close to where helicopters would later deliver bottles of water in black body bags, they rested once again. Sgt. Stephen Byers, 31, of Detroit said that Friday night was the first time he had a chance to call his wife and kids since the search started.

He said that he was too tired to say very much, but that his wife was clearly worried. He had begun to wonder himself if the search was becoming more dangerous. “The more we chase them around,” he said, “the more they know where we’re at.”

But, he said, in a war without front lines and goals that are hard to achieve, the search offered the comfort of certainty, of a clear and noble goal. “If we find them, we accomplish something specific,” Sergeant Byers said. “It’s not like trying to bring peace to the area then finding out later that you didn’t.”

***

Saturday’s searching turned up nothing significant. The three soldiers — Pfc. Joseph J. Anzack Jr., 20, of Torrance, Calif.; Specialist Alex R. Jimenez, 25, of Lawrence, Mass.; and Pvt. Byron W. Fouty, 19, of Waterford, Mich. — were not found.

On Sunday, the group welcomed the return of two of its wounded soldiers — Sergeant Simonovich and Pfc. Nicholas Barker, who had slight shrapnel wounds to the face. American soldiers are not allowed to drink alcohol here, so they had a barbecue. They celebrated. They talked.

And on Monday, it was back to work. The men of Second Platoon prepared their Humvees for another day of walking, another day of searching. They reviewed the route for what would be a seven-mile march that they hoped to do in three hours.

Wearing dark glasses, his uniform bloodstained from two days earlier, Sergeant Delgado, the medic, was a picture of calm. “We had our time to grieve, but after that you have to detach from your emotions and drive on,” he said. “We’re going to be here for another six months.”