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WASHINGTON, D.C. (CBSMiami) — The whistleblower who exposed a Facebook data breach testified before British lawmakers Tuesday saying it’s “categorically untrue” that political consultancy firm, Cambridge Analytica, never used Facebook data.

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British politicians now want to hear from Facebook’s founder. Lawmakers on both sides of the Atlantic are pressuring Facebook CEO Mark Zuckerberg, to testify about the company’s recent data breach.  British members of parliament are requesting Zuckerberg appear before the House of Commons.

“We believe, given the serious nature of the allegations that have been made around the accessing of Facebook user data, that it is appropriate that Mark Zuckerberg give evidence,” said British lawmaker Damian Collins.

Zuckerberg says he will send a senior company executive in his place.

Someone who “did” testify was the whistleblower who says data from more than 50-million Facebook users was harvested by British consultancy firm, Cambridge Analytica.

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“They don’t care whether or not what they do is legal … as long as it gets the job done,” said Cambridge Analytica Whistleblower Christopher Wylie.

Wylie painted a picture of a lawless company that used hacked material, illegal data, and intimidation tactics to win elections including the 2016 presidential election.

“So for you, Donald Trump’s election crossed a line you felt that techniques you were aware of shouldn’t have been used,” said Damian Collins, British lawmaker and Chair of Digital, Culture, Media and Sport Committee.

“Donald Trump makes it click in your head that it has a much wider impact,” said Wylie.

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Last week, U.K authorities raided Cambridge Analytica’s London headquarters, looking for evidence. In Washington, the Federal Trade Commission opened an investigation, as well.