Wells Fargo is still answering for the more than 2 million fake accounts that 5,000 of the bank’s former employees opened in order to get sales bonuses, but now, a group of senators want to know if the bank’s auditor knew about the fake accounts too and whether the auditor did anything about it.

In a letter sent to KPMG, which served as Wells Fargo’s independent auditor from 2011-2015, Sens. Elizabeth Warren, D-Mass.; Bernie Sanders, I-Vermont; Mazie Hirono, D-Hawaii; and Edward Markey, D-Mass. say they want to know whether any of KPMG’s audits uncovered the fake account situation.

And if KPMG didn’t find anything about the fake accounts during its audits, the senators want to know why.

The senators question how KPMG’s audits, which were conducted by “obtaining an understanding of internal control over financial reporting, assessing the risk that a material weakness exists, and testing and evaluating the design and operating effectiveness of internal control based on the assessed risk,” did not uncover the fake accounts.

“Was KPMG aware of any of the illegal sales practices committed by Wells Fargo employees from 2011-2015 and addressed in the CFPB settlement?,” the senators ask in their letter to KPMG.

Read on.