Federal agents expanded their search for the dark, square-jawed"John Doe No. 2" suspect in the Oklahoma bombingto all 56 field offices in the country, and said they are seeking at least two men associated with Timothy McVeigh, the suspect identified Friday. In Oklahoma City, court-appointed attorneys for McVeigh filed papers asking to withdraw from the case. (One of them, John Coyle, said his family had received threats and belatedly offered that he had friends hurt in the blast.) The Pentagon, meanwhile, reported that McVeigh and Terry Lynn Nichols -- a"Militia of Michigan"member now being held as a material witness -- entered the Army on the same day in 1988 and went on to serve in the same infantry unit at Fort Riley, Kan. At the Alfred P. Murrah Building,80 people were confirmed dead today, 13 of them children.