In early 2018, Facebook and a political data-analytics firm named Cambridge Analytica were implicated in a massive data breach.

Personal data from over 87 million Facebook users had been improperly obtained by the political data-analytics firm.

In the subsequent months, Facebook has testified in front of Congress and been slapped with a record $5 billion fine by the Federal Trade Commission.

And now, according to newly uncovered emails from 2015 discussing Cambridge Analytica, it looks like Facebook could've done something to stop the issue before it was too late.

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In early 2018, Facebook admitted to mishandling data from over 50 million Facebook users which had been improperly obtained by political data-analytics firm Cambridge Analytica.

By just a few months later, that number had risen considerably — somewhere in the range of 87 million Facebook users were actually impacted. Facebook apologized, CEO Mark Zuckerberg went in front of Congress to answer questions, and the FTC slapped Facebook with a historically large fine — $5 billion.

Now, in emails recently uncovered by NBC, we're learning that Facebook employees were discussing Cambridge Analytica as far back as September 2015.

Here's the full story thus far: