Lana Padilla with Ron Delpit Shortly after Timothy McVeigh was arrested for the bombing of the federal building in Oklahoma City, police issued a warrant for Terry Nichols, an old army friend of McVeigh's, whom they believed was also involved in the bombing plot. Witnesses told the FBI that Nichols and McVeigh made and exploded small homemade bombs on a farm in Michigan owned by Nichols's brother, James. Authorities also found receipts at Nichols's home—with McVeigh's fingerprints on them—for large amounts of fertilizer and fuel, the ingredients used in the bomb that blew up the Murrah building. The FBI also suspected that Nichols, McVeigh, and perhaps another accomplice robbed a gun and coin dealer as well as nearly two dozen Midwestern banks of more than $250,000 during a two-year spree in 1994 and 1995.

Lana Padilla, Nichols's ex-wife...