Walter Taffet is a agent with the Office of Professional Responsibility who is summoned by the FBI following the discovery of a bug in a pen that Martha Hanson planted in Agent Gaad's office.
Among those suspected is Martha. She and Taffet encounter each other in an elevator and when she questions "Clark", he does not know who Taffet is but coaches her on how to respond to his questions. She passes his questioning but Taffet's presence forces her to face that her husband may not be who he says he is.