Investigators from Britain's data watchdog searched the London offices of Cambridge Analytica, the data analytics firm at the center of a storm over allegations it improperly harvested Facebook data to target U.S. voters.
About 20 officials, wearing black jackets with "ICO Enforcement" on them, arrived at the firm's central London offices on Friday evening soon after a High Court judge granted a search warrant sought by the Information Commissioner's Office (ICO).
The officials concluded the search around 0300 GMT on Saturday. "We will now need to assess and consider the evidence before deciding the next steps and coming to any conclusions," an ICO spokesperson said in a statement.
The officials, who were let into the building by security guards, were seen checking books and papers through the windows of the second-floor offices on London's busy New Oxford Street, a Reuters witness said.
Elizabeth Denham, head of the ICO, sought the warrant after a whistleblower said Cambridge Analytica had gathered private information of 50 million Facebook users to support Donald Trump's 2016 U.S. presidential campaign.
Britain is investigating whether Facebook, the world's largest social media network, did enough to protect data.