On March 9, 2010, the day she revealed her plan to run for the Senate in a press release, a tax lien was placed on a house purported to be hers and publicized. The problem was she no longer owned the house. The IRS eventually blamed the lien on a computer glitch and withdrew it.

Now Mr. Martel, a criminal investigator for the Treasury Department’s inspector general for tax administration, was telling her that an official in Delaware state government had improperly accessed her records on that very same day.

Beyond that, Ms. O’Donnell and Senate investigators who have tried to help her have run into a wall of silence, leaving more questions than answers about whether abuses of the IRS system extend to private individuals and not just the tax-exempt groups already identified as victims.