After Facebook CEO Mark Zuckerberg refused to testify at a joint hearing with lawmakers from seven nations over his company's invasive privacy practices, the U.K. Parliament on Saturday legally seized thousands of secret and "potentially explosive" Facebook documents in what was described as an extraordinary move to uncover information about the company's role in the Cambridge Analytica data-mining scandal.

"This week Facebook is going to learn the hard way that it is not above the law."

—Christopher Wylie, whistleblower

According to the Guardian, the documents were initially obtained during a legal discovery process by the now-defunct U.S. software company Six4Three, which is currently suing Facebook.

Conservative MP Damian Collins, the Guardian reports, then "invoked a rare parliamentary mechanism" that compelled Six4Three's founder—who was on a business trip in London—to hand over the documents, which reportedly "contain significant revelations about Facebook decisions on data and privacy controls that led to the Cambridge Analytica scandal. It is claimed they include confidential emails between senior executives, and correspondence with Zuckerberg."

"This week Facebook is going to learn the hard way that it is not above the law. In ignoring the inquiries of seven national parliaments, Mark Zuckerberg brought this escalation upon himself, as there was no other way to get this critical information," wrote Christopher Wylie, a whistleblower who was previously the director of research at Cambridge Analytica.

"The irony is... Mark Zuckerberg must be pretty pissed that his data was seized without him knowing," Wylie added.

This is really bad for Facebook. https://t.co/hBSJRaedFm — Matt Stoller (@matthewstoller) November 25, 2018

The U.K. Parliament's seizure of documents Facebook has long worked to keep hidden from the public view comes as the social media behemoth is embroiled in yet another scandal, this time over its use of a right-wing public relations firm to spread anti-Semitic conspiracy theories about its critics.

"Facebook will learn that all are subject to the rule of law," Labour MP Ian Lucas wrote on Twitter. "Yes, even them."