ANCHORAGE, Alaska (CNN) -- Alaska Gov. Sarah Palin will not cooperate with a legislative investigation into the firing of her public safety commissioner, the McCain-Palin presidential campaign announced Monday, accusing supporters of Democratic rival Barack Obama of manipulating the inquiry for political motivations.

Gov. Sarah Palin is fighting allegations she improperly tried to force the firing of her former brother-in-law.

Former Palin Press Secretary Meg Stapleton told reporters in Anchorage that the investigation has been "hijacked" by "Obama operatives" for the Democratic presidential nominee -- namely, Alaska state Sen. Hollis French, the Democratic lawmaker managing the investigation and an Obama supporter. French has denied working on behalf of the Obama campaign.

The Obama campaign described Stapleton's charge as "complete paranoia." It has denied sending campaign staff to Alaska to work with the legislative committee's investigation.

McCain campaign spokesman Ed O'Callaghan said Palin will not cooperate with "that investigation so long as it remained tainted and run by partisan individuals who have a predetermined conclusion," referring to a comment by French earlier this month that the case could produce criminal charges or an "October Surprise" for the GOP ticket.

Palin, the Republican nominee for vice president, is battling allegations that she and her advisers pressured then-Public Safety Commissioner Walt Monegan to fire a state trooper going through a bitter custody dispute with her sister -- and that Monegan was terminated when he refused. Palin says she fired Monegan over budget issues and denies wrongdoing.

Monegan has said that while no one directly demanded Trooper Mike Wooten's dismissal, he felt pressured to do so by Palin, her husband and staff. He said he believes his refusal to fire the trooper led to his own firing. Upon the dismissal, Monegan was offered a position as executive director of the Alcohol Beverage and Control Board, but turned it down.

Palin's lawyers say the investigation -- which the Legislature commissioned on a bipartisan basis in July -- belongs before the state Personnel Board, which met to consider the request Thursday. On Friday, Alaska lawmakers voted to subpoena Palin's husband, several aides and phone records in their investigation.

Stapleton said Palin's attorneys have turned over to the board e-mails that contain "new information that exonerates Palin and proves Monegan's egregious insubordination."

Monegan allegedly worked against Palin over his department's budget, making repeated requests to Congress "for funding that was out of line for every other commissioner and agency," she said.

"The final straw came in late June, when Commissioner Monegan arranged for another unauthorized trip to D.C. to request more money from Congress," Stapleton said.

The campaign also disputed recent comments Monegan made to ABC News, in which he accused Palin of lying during her wide-ranging interview with ABC's Charles Gibson last week.

Palin told Gibson, "I never pressured him to hire or fire anybody." She said she welcomed the investigation and did not worry about the subpoena of her husband, Todd Palin.

"There's nothing to hide," she said. "I know that Todd, too, never pressured Commissioner Monegan. He did, very appropriately, though, bring up those concerns about a trooper [Wooten] who was making threats against the first family, and that is appropriate."

Monegan rebutted Palin's comments, saying, "She's not telling the truth when she told ABC neither she nor her husband pressured me to fire Trooper Wooten," according to an interview posted on ABC News.com. "And she's not telling the truth to the media about her reasons for firing me."

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