Big-name conservative politicians, columnists and broadcasters have long hurled thunderbolts at the left-leaning advocacy group ACORN.

But nothing has rocked ACORN quite like a recent series of hidden-camera videos in which a 20-year-old South Florida woman and her 25-year-old accomplice pose as a prostitute and pimp, and appear to get advice from ACORN employees on setting up a brothel and evading taxes.

Hannah Giles, a Florida International University student whose father is the pastor of a church in Aventura, is the scantily clad co-star of the videos along with James O'Keefe, a conservative activist who appears in outlandish, fur-accented pimp garb. The videos -- shot in Baltimore, Washington, New York and San Bernadino, Calif. -- have been an Internet sensation and appear to be taking their toll in Washington, where the U.S. Census Bureau severed ties to the group Friday and the Senate voted 83-7 Monday to block any housing grants to ACORN.

House Republicans have also pushed for legislation to strip money from the group, with U.S. Rep. Gus Bilirakis, R-Palm Harbor, specifically targeting a Federal Emergency Management Agency grant of almost $1 million for ACORN to assess the fire safety of low- and moderate-income homes in New Orleans. Republicans say ACORN has received about $53 million in federal money over the past 15 years, a figure ACORN has not disputed.

White House spokesman Robert Gibbs weighed in as well Wednesday, saying ``obviously the conduct that you see on those tapes is completely unacceptable.''

ACORN, which stands for the Association of Community Organizations for Reform Now, engages primarily in housing assistance, voter-registration drives and income-tax preparation targeted to minorities and the poor.

ACORN's Florida director, Stephanie Porta, said Giles showed up at the group's Miami office by herself in July or August claiming to be a prostitute seeking housing assistance. Porta said an ACORN staffer suggested that she visit a domestic-violence shelter but, unlike ACORN employees caught on video in other cities, did not offer help setting up a brothel or laundering money.

MIAMI OFFICE

The group's Miami housing office has received a federal grant to help people improve their job skills and ``financial literacy,'' but Porta said she did not know the amount of the award.

ACORN initially claimed the videos from the other cities were ``doctored'' and part of a conspiracy involving Fox News, which has aired the tapes extensively. Saying conservatives have made ACORN ``their Willy [sic] Horton for 2009,'' ACORN accused O'Keefe and Giles of breaking the law with their surreptitious taping. ACORN also suggested the videos -- shot during the summer -- were released now in an attempt to derail healthcare reform. But ACORN has conceded the young activists uncovered wrongdoing. ``I cannot and I will not defend the actions of the workers depicted in the video, who have since been terminated,'' ACORN Chief Organizer Bertha Lewis said in a statement.

Wednesday, the group announced it was ordering an independent investigation of its practices. It has also suspended new admissions to its programs and will conduct staff training, Lewis said.

Attempts to reach O'Keefe and Giles for comment this week were unsuccessful.

A biography of Giles at the conservative Townhall.com site says she is as an ``aspiring journalist'' and the daughter of Townhall contributor Doug Giles, who is pastor of the Clash Church in Aventura.

In announcing the independent investigation, ACORN said it would work with its advisory council, which includes prominent supporters of President Barack Obama. During the 2008 presidential campaign, an ACORN-affiliated group received more than $800,000 from the Obama campaign for get-out-the-vote efforts.

Conservatives have long accused ACORN of encouraging voter fraud, and they claimed vindication last week when Miami-Dade prosecutors charged 11 canvassers who had been hired by ACORN with forging signatures on voter-registration applications last year.

The accused workers were turned in by ACORN officials, which the group said was proof that it takes quality control and the integrity of the voting process seriously.

UPROAR OVER VIDEOS

The controversy over the Miami voter fraud charges was quickly eclipsed by the uproar over the videos, in which ACORN staffers don't seem at all fazed when O'Keefe and Giles ask for help getting a house to use as a brothel with underage girls from El Salvador. The workers appear willing to help the duo conceal the source of the income.

ACORN workers in Baltimore, for example, told Giles to describe herself as a ``performing artist'' for tax purposes and suggest she claim some of the underage girls as dependents. A New York ACORN employee counseled Giles to hide her earnings in a tin in the back yard.

During the pair's visit to the ACORN office in California, an employee told O'Keefe and Giles that she had killed her husband. ACORN released a statement saying the employee was suspicious of the pair and fabricated the murder claim as a way to counter ``their outrageousness with her own personal style of outrageousness. She matched their false scenario with her own false scenarios.''

This report was supplemented with information from The Associated Press.