A former U.S. business executive, who abruptly raised the price of a life-saving drug by more than 5,000 percent, refused to answer questions when he appeared before Congress on Thursday.
Martin Shkreli's appearance before the House Committee on Oversight and Government Reform was a chance for lawmakers to sound off on the case, which drew widespread criticism.
But the 32-year-old, who received a subpoena to appear before the hearing, said he was exercising his Fifth Amendment right against incriminating himself.
While he didn't speak at the hearing, he took to Twitter to criticize the lawmakers who were questioning him.
Before stepping down as CEO of Turing Pharmaceuticals, Shkreli raised the price of Daraprim, a drug used by patients with AIDS and certain types of cancer, from $13.50 to $700 a pill.
Shkreli has defended the price hike as legal, saying he was just trying to maximize profits for investors. U.S. political leaders in both parties have criticized the move, calling it an example of "price-gouging."
Separately, Shkreli faces criminal charges of securities fraud related to his leadership role at two other companies: hedge fund MSMB Capital Management and biopharmaceutical firm Retrophin.