Lawmakers representing the Tea Party and other conservative groups targeted by the Internal Revenue Service have released documents showing IRS officials in the nation's capital and at least two other offices in California were also involved in the screenings.
The new evidence contradicts the IRS's initial claims that only their Cincinnati branch was to blame.
One IRS letter asked for information about donors even though applicants seeking tax exempt status are not required to provide such information.
"This should be an American issue where all Americans can come together and say this is not right, this will not stand," Mark West of the Chattanooga Tea Party said.
Jennifer Stefano, state director of Americans for Prosperity-Pennsylvania, tried to start a Tea Party group. But when the IRS sent her a mountain of questions Stefano became frustrated and decided it was easier to quit.
"How many emails did you send? What were they? How many rallies did you go to?" Stefanoy recalled. "It had a chilling effect on all of us."
She blames President Obama.
"It became clear to me that President Obama wasn't really interested in having a political discourse. People like me were the enemy," she said.
Meanwhile, the president called the scandal "outrageous" and vowed that those responsible will be dealt with.
"I've got no patience with it," he said. "I will not tolerate it, and we will make sure we find out exactly what happened."
U.S. Attorney General Eric Holder echoed the president's sentiments and has ordered an investigation of the matter.
The IRS now acknowledges that acting IRS Commissioner Steven Miller has known about the targeting of conservative groups for a year. The agency, however, did not apologize until a few days ago.
In a USA Today op-ed, Miller said the agency was guilty of a lack of sensitivity and took a "shortcut" in determining which groups needed special screening.
"Mistakes were made, but they were in no way due to any political or partisan motivation. We are - and will continue to be - dedicated to reviewing all applications for tax-exempt status in an impartial manner," he wrote.
Miller also wrote that new procedures have been implemented to make sure the mistakes don't happen again.
Members of Congress want to know why they weren't told earlier about the IRS targeting conservative groups. They're expected to grill Miller Friday when he appears before the House Ways and Means Committee in the first of what will likely be many hearings on the scandal.