The Justice Department has reportedly opened a probe into Cambridge Analytica, the defunct data firm that worked for President Trump’s campaign in 2016.

The department, along with the FBI, has started to grill potential witnesses and has relayed to them that there is an open investigation into the firm, according to The New York Times.

The company, which is tied to former Trump aide Steve Bannon and conservative mega donor Rebekah Mercer, is under scrutiny after it was revealed that it harvested data from 50 million Facebook users.

Christopher Wylie, a whistleblower who revealed the massive data heist by the company, confirmed to the Times that he has spoken to federal authorities.

It wasn’t clear if the probe was connected to Special Counsel Robert Mueller’s investigation into Russian interference in the 2016 election.

The newspaper said that the Cambridge Analytica investigation appears to be in its early stages.