Economist Jonathan Gruber apologized before a congressional panel this week for controversial comments he made about the political process behind the Affordable Care Act, but he declined to say how much the Obama administration paid him for consulting work on the health-care law.

Rep. Darrell Issa (R-Calif.) isn’t letting him off the hook. As one of his final acts as chairman of the powerful House Oversight and Government Reform Committee, he issued a subpoena Thursday demanding that Gruber hand over all documents and communications with government officials related to his work on the health-care law.

“As one of the architects of Obamacare, Jonathan Gruber is a unique position to shed light on the ‘lack of transparency’ surrounding the passage of the president’s health-care law,” Issa said in a statement Friday. “The American people deserve not just an apology, but a full accounting, which Mr. Gruber must provide.”

The Obama administration paid Gruber, an economist with the prestigious Massachusetts Institute of Technology, about $400,000 for a system to help predict how the Congressional Budget Office would score the Affordable Care Act. CBO scoring, or quantifying the financial impacts of a bill, can be a major factor in determining whether legislation passes or fails.

Gruber said at a forum several years ago that the creators of the health-care legislation used “tortured language” to keep parts of the measure from being scored as tax increases. He added that “lack of transparency is a huge political advantage” because of “the stupidity of the American voter.”

At a hearing with the oversight committee  Tuesday, Gruber said his comments were out of line, explaining that he made “uninformed and glib” remarks about the political process behind the Affordable Care Act.

“I am not an expert on politics, and my tone implied that I was, which is wrong,” Gruber said. “It is never appropriate to try to make oneself seem more important or smarter by demeaning others. … I am embarrassed and I am sorry.”

Gruber did not immediately respond to an e-mail requesting a response to the subpoena Friday afternoon. A call to his office was not answered.

It is unclear whether Rep. Jason Chaffetz (R-Utah) will decide to enforce the subpoena once he succeeds Issa as chairman of the oversight committee in January. His office did not immediately respond to a request for an answer Friday afternoon.