Price gouger Martin Shkreli lashes out at opponents on Twitter

Under increasing scrutiny of powerful government authorities, former Turing Pharmaceuticals CEO Martin Shkreli lashed out at his opponents on Twitter.

The 32-year-old former hedge fund manager gained notoriety as the ''most hated man in America'' last year after it emerged that his company had jacked up the price of the lifesaving drug Daraprim by 5,000 per cent to $750 a pill from $13.50.

The House Committee on Oversight and Government Reform in a letter to Shkreli has called for his testimony as part of its investigation into exorbitant practices in the pharmaceutical industry. Shkreli posted the letter in his tweet.

The committee was also seeking answers from Turing's chief commercial officer and the interim CEO of Valeant, which had also been accused of price gouging.

According to senator Republican Susan Collins, chair of the Senate Special Committee on Aging, the millionaire was invoking his Fifth Amendment right to not testify.

The Republican said on Twitter yesterday that ''absent a valid justification'' his stand could hinder the investigation of the upper congressional chamber's Special Committee on Aging.

''I have valid justification. Are you serious? I have constitutional rights. No wonder trust in the US Government is at a low,'' the former executive known as ''Pharma Bro'' responded.

Shkreli was arrested last month, in New York, and charged with securities fraud and conspiracy. The charges relate to another pharmaceutical company he previously ran called Retrophin (See: Price-gouging pharma firm's Martin Shkreli arrested for securities fraud ).

According to prosecutors, Shkreli ran his companies "like a Ponzi scheme," an according to US attorney Robert Capers who spoke to reporters, Shkreli weaved an "outrageous web of lies and deceit" to make the scheme work.

In the event of his conviction, Shkreli could face up to 20 years in prison.

On the Senate floor yesterday, Collins and ranking member, Democrat senator Claire McCaskill said Shkreli had asserted his Fifth Amendment privilege in response to a separate subpoena for documents he was issued by their panel last month.

According to both senators, he was improperly asserting his Fifth Amendment rights, given their inquiry into his company's pharmaceutical business ostensibly had nothing to do with his securities fraud case.