Cambridge Analytica

Updated at 12:52 p.m. ET

Cambridge Analytica used Facebook to find and target Americans to trigger paranoia and racial biases, a former employee of the data analytics company told lawmakers on Wednesday.

Updated at 6:16 p.m. ET

Cambridge Analytica, the firm that used data from millions of Facebook users without their knowledge, said Wednesday that it is "immediately ceasing all operations." The firm worked for President Trump's 2016 campaign.

The acting chief executive officer of Cambridge Analytica, the political data firm embroiled in controversy after improperly sharing data from some 87 million Facebook users, has stepped down. Alexander Tayler is the second CEO to step down since the scandal broke in March.

A statement on Cambridge Analytica's website says Tayler will resume his former position as chief data officer "in order to focus on the various technical investigations and inquiries."

Updated at 6:40 p.m. ET

Personal information of up to 87 million people — mostly in the United States — may have been "improperly shared" with Cambridge Analytica, a data analytics firm used by the Trump campaign that has recently come under fire.

Updated at 8:30 p.m. ET

Facebook CEO Mark Zuckerberg will testify on Capitol Hill on April 10 and 11 before the a joint hearing of the Senate Judiciary and Commerce Committees, followed by one before the House Energy and Commerce Committee, to answer questions about how the company protects its users' data.

It has been a bad week for Cambridge Analytica.

Top executives at Cambridge Analytica, the U.K.-based firm embroiled in a controversy over the mining of Facebook user data, have been secretly recorded describing the stealthy methods they used to help get Donald Trump elected.