In March 2000, Callahan was called to testify before Congress regarding her role as White House IT manager during the Clinton administration. Three Northrop Grumman contract workers responsible for operating the system testified that the problem was technical in nature, but that White House staff members Callahan and Mark Lindsay (an assistant to the president and director of White House management and administration) instructed them "to remain quiet on the issue while the problem was diagnosed and repaired." "No witness reported that they were told to lie to investigators or felt they were prevented from reporting matters to the appropriate law enforcement officials," and the contractors did not allege that the problem "actually caused by the White House, nor did the White House tell them to destroy any e-mails." The contractors did testify that the staffers threatened them with being fired or arrested if they spoke about the problem. Callahan and Lindsay "vehemently denied" threatening the contractors, and stated that their instructions to limit "water cooler talk" while the team was in a "diagnostic mode" were standard procedure.