A Washington-based IRS supervisor acknowledged she was personally involved in reviewing Tea Party applications for tax-exempt status as far back as 2010, Fox News confirms -- a detail that further challenges the agency's initial claim that the practice of singling out those groups was limited to a handful of employees in Ohio.

Congressional sources confirmed to Fox News that Holly Paz, who until recently was a top deputy in the division that handles applications for tax-exempt status, told congressional investigators she reviewed 20 to 30 applications. Some requests languished for more than a year without action.

The account undercuts the narrative that senior officials only learned of the practice after it had already started in the Cincinnati office.

Details of Paz's role were first reported by The Associated Press. Still, Paz provided no evidence that senior IRS officials ordered agents to target conservative groups or that anyone in the Obama administration outside the IRS was involved.

Instead, Paz described an agency in which IRS supervisors in Washington worked closely with agents in the field but didn't fully understand what those agents were doing. Paz said agents in Cincinnati openly talked about handling "tea party" cases, but she thought the term was merely shorthand for all applications from groups that were politically active -- conservative and liberal.

Paz said dozens of tea party applications sat untouched for more than a year while field agents waited for guidance from Washington on how to handle them. At the time, she said, Washington officials thought the agents in Cincinnati were processing the cases.

Paz was among the first IRS employees to be interviewed as part of a joint investigation by the House Oversight and Government Reform Committee and the House Ways and Means Committee.

Congressional investigators have interviewed at least six IRS employees as part of their inquiry. The Associated Press has reviewed transcripts from three interviews -- with Paz and with two agents, Gary Muthert and Elizabeth Hofacre, from the Cincinnati office.

The IRS declined comment for this story.

A yearlong audit by the agency's inspector general found that IRS agents had improperly targeted conservative political groups for additional and sometimes onerous scrutiny when those groups applied for tax-exempt status.

The audit found no evidence that Washington officials ordered or authorized the targeting. But the IRS watchdog blamed ineffective management by senior IRS officials for allowing it to continue for nearly two years during the 2010 and 2012 elections.

Since the revelations became public last month, much of the agency's leadership has been replaced and the Justice Department has started a criminal investigation. Both Paz and her supervisor, Lois Lerner, who headed the division that handles applications for tax-exempt status, have been replaced.

Agency officials told congressional aides that Lerner was placed on administrative leave. They did not disclose the status of Paz, other than to say she was replaced June 7.

Lerner is the IRS official who first disclosed the targeting at a legal conference May 10. That day, she told The AP: "It's the line people that did it without talking to managers. They're IRS workers, they're revenue agents."

On May 22 -- the day after Paz was interviewed by investigators -- Lerner refused to answer questions from lawmakers at a congressional hearing, citing her Fifth Amendment right not to incriminate herself.

Paz told congressional investigators that an IRS agent in Cincinnati flagged the first tea party case in February 2010. The agent forwarded the application to a manager because it appeared to be politically sensitive, Paz said. The manager informed Paz, who said she had the application assigned to a legal expert in Washington.

At the time, Paz headed a technical unit in Washington that provided guidance to agents who screened applications for tax-exempt status. The agents worked primarily in Cincinnati. One of their tasks was to determine the applicant groups' level of political activity.

IRS regulations say tax-exempt social welfare organizations may engage in some political activity but their primary mission cannot be influencing the outcome of elections. It is up to the IRS to make that determination.

"It's very fact-and-circumstance intensive. So it's a difficult issue," Paz told investigators.

"Oftentimes what we will do, and what we did here, is we'll transfer it to (the technical unit), get someone who's well-versed on that area of the law working the case so they can see what the issues are," Paz said. "The goal with that is ultimately to develop some guidance or a tool that can be given to folks in (the Cincinnati office) to help them in working the cases themselves."

By the fall of 2010, the legal expert in Washington, Carter Hull, was working on about 40 applications, Paz said. A little more than half had "tea party" in the name, she said.

IRS agents in Cincinnati were singling out groups for extra scrutiny if their applications included the words "tea party," "patriots" or "9-12 project," according to the inspector general's report. Paz said she didn't learn that agents were targeting groups based on those terms until June 2011, about the time Lerner first ordered agents to change the criteria.

Paz said an IRS supervisor in Cincinnati had commonly referred to the applications as "tea party" cases. But, Paz said, she thought that was simply shorthand for any application that included political activity.

"Since the first case that came up to Washington happened to have that name, it appeared to me that's why they were calling it that as a shorthand," Paz told congressional investigators.

Paz said she didn't think the agents in Cincinnati were politically motivated.

"My impression, based on, you know, this instance and other instances in the office is that because they are so apolitical, they are not as sensitive as we would like them to be as to how things might appear," Paz said.

"Many of these employees have been with the IRS for decades and were used to a world where how they talked about things internally was not something that would be public or that anyone would be interested in," Paz added. "So I don't think they thought much about how it would appear to others. They knew what they meant and that was sort of good enough for them."

For several months in 2010, Hull worked closely with Hofacre, the agent in Cincinnati, to review the tea party cases, Paz said. In Hofacre's interview, she complained that Hull micromanaged her work.

Hofacre left for a different IRS job in October 2010 and was replaced by an agent whose name was blacked out in the transcript. Paz said the new agent sat on the tea party applications for more than a year because he was waiting on guidance from Washington on how to proceed. Officials in Washington, however, thought the agents in Cincinnati were still processing the cases, she said.

As a result, many applications languished for more than a year, which, the inspector general said, hurt the groups' ability to raise money.

"I knew they were waiting for guidance," Paz said. "I did not know that they were not working the cases because what had been done previously was, they were working the cases in consultation with Washington. And I was under the impression that that was continuing."

Hull was to be interviewed by congressional investigators on Friday. Efforts to reach Hull and Paz for comment were unsuccessful.

In all, agents singled out 298 applications for additional scrutiny because the groups appeared to be involved in political activity, the inspector general's report said. But IRS agents in Cincinnati weren't given adequate training on how to handle the cases until May 2012, the report said.

Before the training, only six applications had been approved. Afterward, an additional 102 applications were approved by December 2012, the report said.

Of those 102 applications, 29 involved tea party, patriots, or 9-12 organizations, the report said. Many applications are still awaiting action. None has been rejected, according to the IRS.

The Associated Press contributed to this report.