Two senators confirmed that a Facebook whistleblower will testify in front of the U.S. Senate next week regarding the company’s “toxic effects” on young users.

According to reports by Fox Business:

“This whistleblower’s testimony will be critical to understanding what Facebook knew about its platforms’ toxic effects on young users, when they knew it, and what they did about it,” Democratic Senator Richard Blumenthal, head of a subcommittee of the Senate Commerce panel, said in a statement announcing the Oct. 5 hearing.

Senator Marsha Blackburn, the subcommittee’s top Republican, said: “From turning a blind eye to the negative impacts of its platforms on teens’ mental health to its inability to police for trafficking, domestic servitude, and other harmful content, Facebook has a lot to account for.”

The announcement came a day after Instagram, the photo-sharing service owned by Facebook, said it had hit a pause on a new app it is creating for children amid growing criticism from U.S. lawmakers and advocacy groups.

The testimony follows a bombshell report from The Wall Street Journal detailing the company’s choice to look the other way for rules violations by “elite” users as well as the company’s knowledge of the negative effects the apps have on younger users, especially teenage girls.