The Republican Party of Delaware has filed a formal complaint with the Federal Election Commission, accusing one of its own Senate candidates of illegally collaborating with the Tea Party Express.

Attorneys for the state party asked the FEC to launch an immediate and thorough investigation into conservative GOP candidate Christine O’Donnell “to remedy the alleged violations and to ensure that these violations immediately cease and do not reoccur,” according to the complaint filed Thursday.

O’Donnell, who faces Rep. Mike Castle in Tuesday’s primary, came under fire from the state party shortly after tea party-backed candidate Joe Miller upset Sen. Lisa Murkowski in the Alaska GOP primary.

Following the Alaska race, the Tea Party Express redirected its efforts to Delaware. The organization’s chairwoman, Amy Kremer, said that 10 staffers are on site and vowed to spend $250,000 to help O’Donnell before the primary.

The complaint alleges that the O’Donnell campaign is “knowingly accepting illegal campaign contributions from the Tea Party Express” political action committee. It cites two “alarming” instances:

— O’Donnell has knowingly accepted excessive contributions from the Tea Party Express that were directly solicited on behalf of the O’Donnell campaign, according to the filing.

— O’Donnell has accepted illegal excessive contributions from the Tea Party Express by engaging in a statewide coordinated communications effort in support of her campaign. This means, according to the complaint, that every advertisement that is being run by the Tea Party Express in support of O’Donnell is a violation of federal law.

The issue won’t be resolved before Tuesday.

An FEC spokeswoman said it was “highly unlikely that the case could be expedited before the primary.”

Delaware State GOP Chairman Tom Ross offered this statement:

“Christine O’Donnell needs to immediately call upon her third party supporters to cease and desist this illegal behavior,” he said. “This type of behavior has no place in our political process, and O’Donnell should denounce these illegal ads. Donors deserve to know whether they made an illegal donation so they can demand a refund and get their money back.”

Neither the Tea Party Express nor the O’Donnell campaign could immediately be reached for comment.