AD DWAR, Iraq, Dec. 20 — Before his capture in a coffinlike underground bunker outside this bleak town, Saddam Hussein spent months moving furtively among 20 or 30 nondescript safe houses in the Sunni Muslim heartland, where a tightknit network of family and clan sheltered him and brought him news from across American-dominated Iraq, American military officials say. With that, he used a word-of-mouth system of couriers to carry his instructions back to a cluster of Baathist cells that helped him guide the anticoalition insurgency, the Americans say. The 66-year-old Mr. Hussein traveled on foot, by small boat along the...