Members of the U.S. House Committee on Oversight & Government Reform penned a letter to Mylan (NSDQ:MYL) demanding a more complete look at the pricing of its EpiPen epinephrine auto-injector.

At a Sept. 21 congressional hearing, Mylan CEO Heather Bresch testified that the company makes a $100 profit per 2-pack of EpiPens. Last week, Mylan clarified that its operating profit is actually $166 before taxes and that the number it presented before the Senate reflects the U.S. statutory rate of 37.5%. Mylan’s overall tax rate is much lower, according to the Wall Street Journal.

The Canonsburg, Pa.-based company has been under fire since August, when reports revealed that it has raised the price of its EpiPen product by more than 500% since 2007. Bresch maintained that the problem stems from a system involving wholesalers, pharmacies, and pharmacy-benefit managers, who each take a cut of every prescription.

Oversight & Government Reform chairman Rep. Jason Chaffetz (R-Utah) and ranking member Rep. Elijah Cummings (D-Md.) wrote that Bresch’s testimony “omitted key tax assumptions that affect the company’s profit per pack” and “raises questions” about the company’s transparency.

The committee leaders wrote that they expect Mylan to provide all documents related to sales, profits, costs, manufacturing and distribution, Bresch’s notes for the congressional hearing, documents related to Mylan’s tax rates since 2007, and a comment on whether Mylan plans to try and extend market exclusivity for the EpiPen. The deadline for Mylan to respond with the requested information is Oct. 7.

“We remain committed to productive and continued cooperation with the committee, and we intend to respond to their request for additional information,” a Mylan spokesperson said, according to the Journal.

Mylan’s shares dropped -10% to $42.64 apiece when the criticism began in August. Since then, shares have slowly but steadily declined. The stock was trading at $37.46 per share in mid-morning activity today, down -1.1%.