This raised my eyebrow:

[U.S. Attorney Karin] Immergut said a pledge by the defendants to never reveal each other’s identities to law-enforcement officials made the investigation more difficult. But investigators persuaded some alleged participants to act as informants, providing details of the crimes.

[40-year-old Arizona bookstore owner William C.] Rodgers, who also was identified by federal prosecutors as the mastermind of the 1998 arson at Vail, Colo., but was not charged in connection with that crime, committed suicide last month in an Arizona jail.

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From the indictment, Rodgers appeared to be a key figure in the cell, allegedly involved in many of the most high-profile crimes.