British officials asked Facebook on Monday to pull auditors it hired to investigate Cambridge Analytica , the political research firm that was involved in a massive data breach during the 2016 U.S. presidential election.

In a statement, Facebook said forensic auditors from cybersecurity company Stroz Friedberg were on site at Cambridge Analyticas London office on Monday evening until they were asked to leave.

At the request of the U.K. Information Commissioners Office, which has announced it is pursuing a warrant to conduct its own on-site investigation, the Stroz Friedberg auditors stood down, Facebook said .

Facebooks auditors had reportedly entered Cambridge Analyticas office before British and European Union investigators could investigate.

British Information Commissioner Elizabeth Denham said Monday that she was requesting a warrant to access Cambridge Analyticas servers after the firm didnt cooperate with an investigation into whether it illegally acquired and used Facebook users data.

Antonio Tajani, president of the European Parliament, also said the European Union would investigate whether European citizens privacy rights had been violated.

Damian Collins, member of Parliament for the Conservative Party, said in a tweet on Monday: These investigations need to be undertaken by the proper authorities.

Facebook announced earlier Monday that it had hired Stroz Friedberg the same digital forensics firm Uber hired to investigate a dispute over intellectual property to audit Cambridge Analytica.

The tech company suspended Cambridge Analyticas account Friday, saying it had obtained personal information from users three years ago in violation of Facebook policy . Strategic Communication Laboratories, the company that owns Cambridge Analytica, was revealed to have harvested data on 50 million Facebook users, according to investigations by The New York Times and The Observer .

That data reportedly helped fuel Donald Trump s presidential campaign by building psychographic profiles about voters without their knowledge.