Both Cruz and his chief rival for the Republican presidential nomination, Donald Trump, used the firm throughout the campaign to target voters they believed might be sympathetic to their causes, according to Federal Election Commission filings.
Here's what you need to know about the firm and Cruz's involvement with it.
1. How Cambridge Analytica got the data.
According to the Times, Cambridge Analytica bought the data from Aleksandr Kogan, a Russian-American academic. Kogan, who told Facebook he was conducting academic research, built a Facebook personality quiz app called "thisisyourdigitalife." When users downloaded the app, it scraped all of their available Facebook data, including their friends, their likes and where they lived.
More than a quarter-million Facebook users downloaded the app, which also exploited a Facebook vulnerability that allowed it to to collect most of the same data from the friends of those who downloaded it. By prying into the friends lists of those who made the download, Kogan was able to get data from more than 50 million people.
2. What did Facebook do about the breach?
Very little at the time, according to The Guardian. When it first found out about the breach in late 2015, Facebook got in touch with Cambridge Analytica, which claimed it didn't know that the data was harvested illegally but would destroy it. Facebook was apparently satisfied until it learned of the Times' and Guardian's new reporting. On Friday, Facebook suspended the firm from running its pages on Facebook and purchasing ads on the site.
3. Where does Cruz come in?
Throughout 2015 and into 2016, the Cruz campaign paid Cambridge Analytica almost $6 million for data that the campaign used for what it called "psychographic targeting," which supposedly allowed the campaign to tailor its message to specific voters in places like Iowa and New Hampshire, where single voters can make a big difference. Using data from the firm, the campaign built profiles of potential voters, prioritizing those who fit in categories such as "stoic traditionalist" and "true believer."
4. Cruz's campaign spokesman spoke glowingly about Cambridge Analytica, even as information about some of the firm's shady data practices became public.
In December 2015, the same month The Guardian revealed Cambridge Analytica and Kogan's data harvesting practices, Cruz campaign spokesman Rick Tyler called the company a "market leader and the best in the field."
“My understanding is all the information is acquired legally and ethically with the permission of the users when they sign up to Facebook,” he said.
5. Cruz's campaign didn't feel like it got its money's worth from the firm.
In March 2017, after the campaign was over, Tyler, who no longer works for Cruz, told the Times that the firm's data was unreliable. During the Oklahoma primary in March 2016, Tyler said, more than half of people identified by the firm as potential Cruz voters supported other candidates.
"When they were hired, from the outset it didn't strike me that they had a wide breadth of experience in the American political landscape," Tyler said.
Despite Tyler's claim that the Cruz campaign stopped using the firm's data in early 2016, it kept paying Cambridge Analytic until June of that year, a month after Cruz suspended his campaign. After Cruz dropped out of the race, the firm began working with Trump, supporting him through November's general election against Hillary Clinton.