About two dozen Tea Party groups filed a lawsuit Wednesday that they said will prove the Internal Revenue Service's practice of targeting conservative groups was cleared by top IRS officials in Washington and was not the work of low-level rogue agents in Ohio.

The federal lawsuit includes 15 letters sent to the Tea Party groups by the IRS asking detailed, often invasive questions about their operations after the groups applied for tax-exempt status. The letters were signed by Lois Lerner, head of the IRS division that oversees tax-exempt organizations, who insists there was no political motivation for singling out groups with "Tea Party," "Patriot" or "9/12" in their names.

The letters, sent in March and April 2012, required the groups to respond in detail within 60 days. But conservatives said the questionnaires were part of a deliberate IRS effort to delay granting the conservative groups tax-exempt status in time for them to oppose President Obama and other Democrats in last year's elections.

"The paper trail from the IRS director of exempt organizations clearly shows that this targeting scheme was not confined to one office in Ohio or originated with a couple of rogue IRS employees as the tax agency contends," Jay Sekulow, the attorney representing the groups, told The Washington Examiner.

The questions sought details about each group's activities, members, resources and public engagement. Groups were asked to list any political candidates they had invited to their meetings or public forums and for a list of those who actually showed up.

"Does your organization promote or publicize itself using any internet social media such as Facebook?" one question asks. "If so, please list the social media outlets and provide hard copy printouts of those outlets."

Sekulow provided to The Examiner letters that the Tea Party groups received from the IRS offices in Washington and California, an indication that the targeting was not confined to one office in Ohio.

Those targeted by the IRS said they hope the lawsuit forces the IRS to disclose documents and other evidence that will show exactly who approved the targeting in the first place. While the IRS insists it was the work of rogue agents, lawmakers say officials far higher up in the agency and Obama administration could have set it in motion.

Catherine Engelbrecht is suing the IRS for the expenses she incurred in her failed attempt to get tax-exempt status for her group, True the Vote. Among her problems with the IRS, Engelbrecht said, was the one-week deadline the agency gave her to answer 200 questions about her group.

Engelbrecht said she talked with the agents in the Cincinnati office whom the IRS blamed for the targeting and determined those agents were not in control of the approval process.

"I was told on two separate occasions," Engelbrecht said, "that they were waiting to get their instructions from Washington."

Lerner has been placed on paid administrative leave.