US politician Christine O'Donnell, who unsuccessfully ran for Delaware's senate seat, has denied accusations that she improperly used campaign funds for personal expenses.
Federal investigators have launched a criminal probe into the alleged misuse.
Ms O'Donnell told ABC News that the charges were a "thug political tactic".
Ms O'Donnell, who won an upset victory in the Republican primary, was endorsed by Sarah Palin and made news for saying she had "dabbled in witchcraft".
Two former campaign aides have alleged that Ms O'Donnell used campaign funds to pay personal expenses including rent.
"There's been no impermissible use of campaign funds whatsoever," Ms O'Donnell told ABC.
In an interview with Fox News, Ms O'Donnell suggested that former staff members of Vice-President Joe Biden - who previously held the senate seat she contested - were behind the accusations, which she says are politically motivated.
"Given that the king of the Delaware political establishment just so happens to be the vice-president of the most liberal presidential administration in US history, it is no surprise that misuse and abuse of the FBI would not be off the table," she told NBC television.
This is not the first time Ms O'Donnell has accused the vice-president of interfering with her career, but the accusations are unsubstantiated.
The investigation will look at each of her three consecutive failed bids for the US senate, dating back to 2006.
After winning a surprise victory over the Republican establishment's preferred primary candidate, Ms O'Donnell went on to raise $7.2m (£4.7m), a record for Delaware.
Her fundraising success was driven by ardent support from the Tea Party movement.
But she was beaten by a wide margin by the Democratic candidate, Chris Coons in the November election.