Facebook has uncovered emails that appear to show chief executive officer Mark Zuckerberg’s connection to potentially problematic privacy practices at the company, the Wall Street Journal reported on Wednesday.

The emails were uncovered as part of a Federal Trade Commission (FTC) investigation that began after the Guardian reported that the personal data of some 50 million Facebook users had been improperly harvested by Cambridge Analytica, a data firm that worked on Donald Trump’s election team and the winning Brexit campaign.