Internal Revenue Service officials sent the Federal Bureau of Investigation a "massive" database listing of tax exempt organizations just a few weeks before the November 2010 elections, House investigators announced Monday.

Oversight and Government Reform Chairmen Darrell Issa, R-Calif., and Jim Jordan, R-Ohio, say they recently obtained an email from Lois Lerner, the former head of the IRS tax exempt division, to a Justice Department official asking how to format the list of tax exempt groups for delivery to the FBI.

Issa, who heads the oversight committee and Jordan, who chairs a subcommittee, said in a statement on Monday they sent a new letter to the IRS, demanding more information about the data sent to the FBI.

"At the very least, this information suggests that the IRS considered the political speech activities of nonprofits to be worthy of investigation by federal law-enforcement officials,” the letter states.

According to Issa and Jordan, the IRS apparently realizes it should not have sent the information to the FBI.

“After the Justice Department turned over the database to the Oversight Committee this month in response to a subpoena, the Justice Department says it was informed by IRS officials that it contains legally protected taxpayer information that should not have ever been sent to the FBI and it now plans to return the full database to the IRS,” a statement from the oversight committee said.

According to material obtained by the committee, the IRS sent the FBI "21 disks constituting a 1.1 million page database of information from 501(c)(4) tax exempt organizations, to the Federal Bureau of Investigation."

The transaction occurred in October 2010.

"The IRS apparently considered political speech by nonprofit groups to be so troublesome that it illegally assisted federal law-enforcement officials in assembling a massive database of the lawful political speech of thousands of American citizens, weeks before the 2010 midterm elections, using confidential taxpayer information," Issa and Jordan said in the letter.

Rep. Elijah Cummings, of Maryland, who serves as the top Democrat on the Oversight panel, said in an email to the Washington Examiner that the information sent to the IRS came from the IRS department that handles public information requests, suggesting that nothing was protected taxpayer information.

“It should come as no surprise that Chairman Issa’s latest letter and press release omit key facts that undermine his breathless claims of a government conspiracy," Cummings said. "Rather than continuing to make such desperate accusations, the Committee should begin focusing on ways to clarify and improve the process of applying for tax exempt status.”

Lerner was recently found in contempt of Congress for refusing to testify about her involvement in a pattern of targeting conservative groups seeking tax exempt status.

In recent weeks, the oversight panel has obtained new information from the IRS after issuing subpoenas.

This story was updated at 8:04 p.m.