Officials with the federal agency now under congressional investigation over a lavish conference were captured on camera joking about the expense at the summit's "capstone" event in October 2010.

One official joked about how much was spent at a party hosted by the agency's commissioner. Another employee, in a mock music video, even sang about how he'd "never be under OIG investigation."

OIG stands for Office of Inspector General -- the office that earlier this week released a bombshell report that triggered firings at the agency that held the conference. The report found the Public Buildings Service, part of the General Services Administration, spent more than $820,000 on the meeting near Las Vegas in 2010.

Two House committees now are probing the agency. One of those, the House Oversight and Government Reform Committee, posted video of the GSA employees online.

Committee Chairman Darrell Issa said a briefing Thursday by the Office of the Inspector General shows former General Services Administrator Martha Johnson and Steven Leeds, former senior counselor to the administrator, were told in May 2011 about the investigation of the conference.

“This administration knew about the spending scandal 11 months ago and they didn’t act until this week,” Mr. Issa said.

Issa, R-Calif., summarized the highlights of the briefing in a letter to Brian D. Miller, inspector general for the General Services Administration.

The video shows one employee performing in the fake music video, which is laced with jokes and references that only federal employees are likely to get.

In the lyrics, the employee sings: "Donate my vacation, love to the nation, I'll never be under OIG investigation."

The creator was given an award at the conference, and named "commissioner for a day."

In the award speech, an official identified as Public Buildings Service Deputy Commissioner David Foley joked that "there's just a couple of small matters."

"The hotel would like to talk to you about paying for the party that was held in the commissioner's suite last night," he said, to uproarious laughter from the crowd.

The inspector general's office detailed in its report that a party was hosted by the actual commissioner in his "loft suite" for senior officials -- at a cost of nearly $2,000.

This and other parties, the report said, did not "fit any legal authority for GSA to spend funds on food."

The Public Buildings Service commissioner, Robert Peck, was fired in the wake of the report, as was another GSA official. The chief at GSA also resigned.

In a statement Thursday, the GSA condemned the contents of the conference video.

"This video is another example of the complete lack of judgment exhibited during the 2010 Western Regions Conference. Our agency continues to be appalled by this indefensible behavior, and we are taking every step possible to ensure that nothing like this ever happens again," a spokesman with the agency said.

The spending habits of the GSA and its subsidiary buildings service have attracted widespread attention in Washington.

Republicans on the House transportation committee on Thursday wrote a letter to the GSA inspector general asking for information about an incentive program they claim handed out "$200,000 worth of taxpayer funded iPods, electronics and gift cards for questionable reasons at best."

Rep. Jeff Denham, R-Calif., accused the administration of treating "hardworking taxpayer dollars like their own private slush fund."

Separately, the nonprofit advocacy group Cause of Action wrote to other federal departments asking them to disclose spending on "commemorative" items -- after the GSA was accused of spending more than $6,000 on commemorative coins at the conference.