GSA official Jeffrey E. Neely appeared Monday before a House panel investigating the GSA spending scandal. (J. Scott Applewhite/AP)

In letters dated April 13, the agency told Robert A. Peck, Jeffrey E. Neely and Robert Shepard to repay expenses for a party they held during the conference at the M Resort. Peck is former head of GSA’s Public Buildings Service; Neely is a former top official in the agency’s western region; and Shepard served as Neely’s chief of staff. Peck resigned three weeks ago when word of the scandal first broke, while Neely and Shepard remain on administrative leave.

On Monday, Neely declined to testify at a House Oversight and Government Reform Committee hearing on the scandal, invoking his Fifth Amendment right to avoid self-incrimination

In separate letters, Peck is told to repay $1,960, Neely is told to pay $2,717.09 and Shepard is told to repay $922.90 “for a party you held in your room at the M Resort.”

“It is unconscionable that the American taxpayer should bear this cost,” say the letters, sent by Public Buildings Service acting Commissioner Linda C. Chero. “You are responsible for this unacceptable expenditure; therefore, I demand that you make payment.”

The letters tell Peck, Neely and Shepard to repay the money by check and send it to a GSA post office box in St. Louis that collects miscellaneous expense receipts.

It was not immediately clear whether any of the three men planned to repay the money.

Follow Ed O’Keefe on Twitter: @edatpost

This post has been updated since it was first published.