Top Republicans on the Senate Commerce Committee pressed Google’s chief executive officer on Thursday to produce an internal memo that suggested the tech giant keep private its discovery that vulnerabilities in a social networking platform had exposed user information.

Google didn’t disclose early this year a finding that private data from as many as 500,000 Google Plus users had been accessible to app developers out of concern about heightened regulatory scrutiny, according to the Wall Street Journal, which described a memo on the matter. Social media giant Facebook was facing a firestorm of criticism at the time over reports that a consultant to President Trump’s 2016 campaign, Cambridge Analytica, had improperly gained access to information on 87 million of its users.