Maybe Mapes was working a Timothy McVeigh angle.
The date of the letter from the warden to Mapes was November 20, 2001. McVeigh was executed on June 11, 2001. If she was working on a McVeigh angle, she was a little late. Of course, there's no date mentioned in the letter as to when she was doing her little favor for Peter Langan. She may have been in contact with Langan for an inside angle McVeigh prior to his execution--but he had been transferred to Terre Haute a number of months before his execution.