Prosecutors have questioned former employees, as well as banks that handled its business, telling potential witnesses there's an open investigation into the firm, unidentified sources told the Times. But prosecutors have shared few details, and the investigation into the company and its business practices appears to be in its early stages.
Cambridge Analytica is at the heart of a scandal that's stirred up two national governments and the world's largest social network. Facebook banned the UK-based political-data analysis firm in March, saying it had improperly received as many as 87 million user profiles leaked from Facebook's service.
Facebook has said a Cambridge University lecturer named Aleksandr Kogan collected the data legitimately through a personality-quiz app but then violated Facebook's terms by sharing the information with Cambridge Analytica, a firm later hired by the Trump presidential campaign during the 2016 US election.
Facebook learned of the infraction in 2015 but didn't inform the public. Instead, the company demanded that all the parties involved destroy the information. But now there are reports that not all the data was deleted.
Cambridge Analytica has denied wrongdoing but said the controversy weighed on its business, and it announced earlier this month that it had decided to shut down.
The Justice Department didn't immediately respond to a request for comment.
Security: Stay up-to-date on the latest in breaches, hacks, fixes and all those cybersecurity issues that keep you up at night.
Blockchain Decoded: CNET looks at the tech powering bitcoin -- and soon, too, a myriad services that will change your life.