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Employees at the obscure General Services Administration are quietly gobbling up 10 percent of the entire federal government's bonus checks, a top Republican lawmaker revealed Wednesday, with the tab reaching a stunning $44 million last year.

The $44 million amount is far more than was previously reported. As House lawmakers convened a hearing Wednesday digging deep into alleged mismanagement and waste at the embattled agency, Transportation Committee Chairman John Mica, R-Fla, called the latest revelations "absolutely outrageous."

Disclosing the results of what he described as a preliminary investigation, Mica said bonuses totaled $44 million, with many bonuses worth $50,000 apiece and some going to workers now under investigation. One employee, he said, received a $79,000 bonus, adding up to nearly $260,000 in total compensation.

Lawmakers also said overtime payments were over the top. Mica cited one case where a worker with an $84,000 salary received $115,000 in overtime.

"There's something wrong at GSA when you have to pay an employee $115,000 in overtime," he said.

Though agency bonuses were worth 10 percent of all government bonuses, Mica said, GSA staff makes up just 1 percent of the total federal workforce.

The hearing Wednesday served as the latest forum for scandalous details to emerge about the agency that is responsible for managing federal property. That agency has been thrust into the congressional spotlight in the wake of the controversy over a 2010 conference in Las Vegas. It turns out, Mica said, that up to 77 conferences are now under investigation.

The $44 million in bonuses was first reported by WUSA. GSA officials at the hearing Wednesday could not confirm the bonus figures. D.C. Delegate Eleanor Holmes Norton said she found it "difficult to believe."

A GSA spokesperson neither disputed nor confirmed the bonus figure when asked later by FoxNews.com.

"Acting Administrator Dan Tangherlini is reviewing all bonuses and the entire performance award system as part of his comprehensive, top to bottom review of all agency operations," the spokesperson said. "This review has already uncovered clear deficiencies in the area of performance awards. In response, Tangherlini has cut executive bonuses and instituted a hiring freeze across the agency."

Rep. Donna Edwards, D-Md., expressed concern at Wednesday's hearing that all the troubling news was casting ordinary GSA employees in a bad light. She called on Tangherlini, who was not present Wednesday, to appear before the committee. She said lawmakers should "defend" hard-working employees at the agency, but not the "garbage" that's wasting taxpayer dollars.

Still, while Mica's panel held the hearing Wednesday, the GSA was holding yet another conference -- this one at the sprawling Opryland convention center in Nashville, Tenn.

The 2012 GSA SmartPay Training Conference runs from Tuesday to Thursday this week. It's for banks investing in the agency's so-called SmartPay system, but also invites a range of officials within GSA.

The visuals of the Nashville conference will likely prove irresistible to lawmakers Wednesday who are looking for examples of GSA's over-spending. GSA, though, defended the conference, saying it is "required and is held to improve the management of (the) government charge cards program."

Cynthia Metzler, GSA's chief administrative services officer, also defended the actions the agency is taking to reform.

She said Wednesday that under new leadership, GSA has canceled 37 previously scheduled conferences and is conducting a "top-to-bottom" review.

She acknowledged that there is a "pattern of mismanagement" spanning multiple administrations, and said "it must stop."

Inspector General Brian Miller, who also testified, said the agency is cooperating with his investigation.

Documents obtained exclusively by Fox News show dozens of conferences in recent years, as well as millions of dollars worth of bonuses handed out to employees. At one controversial conference held in suburban Washington in 2010, more than 3,700 employees received bonuses averaging about $1,000 apiece at the conference. The cost to taxpayers was $3.6 million.

Fox News' FOIA request found several GSA conferences have no record of spending -- no receipts and no way to account for the cost associated with travel and conference spending.

Questioned about the lack of accountability, a GSA spokesman sent a written response to Fox News which said:

"As of April 2012 all spending for events, including training conferences, leadership events, team building exercises, award ceremonies, were suspended. The 2010 awards ceremony was an annual event and has been in existence going back to 2002. Under the new GSA leadership these events and this type of spending are not tolerated."

Fox News' Chad Pergram and Doug McKelway contributed to this report.