Turing Pharmaceutical’s dramatic and rage-inducing decision to jack up the price of a life-saving drug, Daraprim, by more than 5,000 percent is now under investigation by the Federal Trade Commission, according to a lawyer for the pharmaceutical company’s now former CEO, Martin Shkreli.

Shkreli’s lawyer, Baruch Weiss, disclosed the FTC investigation in a letter to the US House of Representatives' Committee on Oversight and Government Reform, which had subpoenaed Shkreli to appear in a January 26 hearing to discuss the same price hike. Weiss cited the FTC probe as the reason that Shkreli would refuse to answer the committee’s questions, invoking his Fifth Amendment right not to incriminate himself, according to Reuters, who broke the story and saw the letter.

In the letter, Weiss wrote that Shkreli would "gladly cooperate" with the House committee if it granted Shkreli immunity. However, such immunity, if granted, would unlikely be granted in time for next Tuesday’s hearing.

In Shkreli’s place, Turing’s chief commercial officer, Nancy Retzlaff, will testify at the hearing, according to the company. But the committee’s chair, US Representative Jason Chaffetz, wrote in a response letter that the panel "rejects the notion that Mr. Shkreli is unable to comply with the subpoena."

Turing and Shkreli are also in the crosshairs of a Senate Committee looking into price gouging in the pharmaceutical industry. Last month, the Senate’s Special Committee on Aging subpoenaed Shkreli for documents in connection with Daraprim’s pricing. And, this week, it was reported that Shkreli would not comply with that subpoena either, again invoking his Fifth Amendment rights.

Meanwhile, Shkreli has been openly mocking the subpoenas, sparring with legislators, and asserting his constitutional rights on Twitter.

The spat with lawmakers and the newly disclosed FTC probe are just the latest troubles facing the reviled former CEO. In December, Shkreli was arrested and indicted on securities fraud for allegedly running a Ponzi-like scheme and swindling another pharmaceutical company he headed, Retrophin, out of millions of dollars. Shkreli is currently out on a $5 million bond he posted with a $45 million E-trade account.

Soon after his arrest, he stepped down as CEO from Turing and was fired as CEO of another pharmaceutical company, KaloBios.

Despite the high-profile investigations, Shkreli’s original claim to infamy goes back to the price-hike of Daraprim last September. As CEO and founder of Turing, Shkreli raised the price of the drug from $13.50 a pill to $750. The drug, which treats a parasitic infection called toxoplasmosis, is often given to AIDS patients and babies.