The General Services Administration official at the center of a scandal over lavish government spending declined to answer questions at a congressional hearing on Monday, invoking the Fifth Amendment.

“Mr. Chairman, on the advice of my counsel I respectfully decline to answer based upon my Fifth Amendment constitutionally privilege,” Jeff Neely, the GSA official, said repeatedly in response to a string of questions from Rep. Darrell Issa (R-Calif.), the chairman of the House Oversight and Government Reform Committee.

Issa had subpoenaed Neely for his role in organizing a 2010 Las Vegas conference of the GSA’s Public Buildings Service, for which Neely serves as a regional commissioner.

A damning GSA Inspector General report, released earlier this month, detailed the almost $823,000 taxpayer-funded tab for the conference, including $146,527 for catered food, $6,325 for commemorative coins and $75,000 for a cooperation-building exercise to construct bicycles.