Laura Callahan, the Homeland Security Department's deputy chief information officer who has been on paid administrative leave since last June after her academic credentials were questioned, resigned today. Also, Drew Ladner, the Treasury Department's chief information officer, has told his staff that he will be leaving the office. Callahan, who was deputy CIO at the Labor Department before DHS tapped her for the department's post, had apparently procured her academic degrees from a diploma mill, an unaccredited institution that dispenses degrees for little or no work. She was put on leave after Congress held hearings to question if she was qualified for the job. Ladner manages a $2.6 billion information technology budget and is a prominent figure on many intergovernmental committees. In the year since he became CIO, Ladner has been recognized for advancing e-government, improving IT security and introducing a new approach to IT governance in the department. During Ladner's tenure, the Treasury CIO's office gained the authority to approve all IT spending, including the Internal Revenue Service's spending on systems modernization projects. Mike Parker, deputy CIO, most likely will become acting Treasury CIO.