The Senate Judiciary Committee will hold a hearing featuring testimony from Twitter whistle-blower Peiter “Mudge” Zatko on Sept. 13, the panel’s leaders announced on Wednesday.

The committee said it had subpoenaed Zatko, the company’s former security chief, to appear a day after he went public with allegations that Twitter has failed to adequately protect data on its hundreds of millions of users, leaving their personal information open to hackers and spies.

“Mr. Zatko’s allegations of widespread security failures and foreign state actor interference at Twitter raise serious concerns,” said Senator Dick Durbin of Illinois, the chair of the Senate Judiciary Committee, and the panel’s top Republican, Chuck Grassley of Iowa.

“If these claims are accurate, they may show dangerous data privacy and security risks for Twitter users around the world,” the senators said in the statement.