Facebook said it ensured the data used by Cambridge Analytica had been deleted, but UK's Channel 4 News found some circulating online.
The data used by Cambridge Analytica -- data that Facebook said had been deleted -- may still be circulating.
Channel 4 News saw some of the information, which included details on 136,000 individuals from Colorado, according to a report by the UK broadcaster.
The data, which Cambridge Analytica inappropriately used in crafting political ads after a researcher collected it from the social network, is at the core of a privacy scandal roiling Facebook. The data was drawdraws from 50 million Facebook users and included profiles of people's personalities and psychological details.
"What happened with Cambridge Analytica represents a breach of trust for which we are very sorry," Paul Grewal, vice president and deputy general counsel, said in a statement. "It is now clear to us that there's more that we could have done, and as Mark Zuckerberg said, we are working hard to tackle past abuse and are committed to letting people know if their data was inappropriately accessed or misused."
Facebook said early on that all of the data obtained by Cambridge Analytica was destroyed.
Zuckerberg, Facebook's CEO, has had to apologize publicly for the incident, and lawmakers have clamored for him to testify before Congress about the matter. Facebook, meanwhile, has offered its users new ways to better control who has access to their data.
Cambridge Analytica said it never passed the data to an external party, and that it deleted the information after Facebook contacted it in 2015. The firm didn't comment on the Channel 4 report.
Update, 3:09 p.m. PT: Adds statement from Facebook.
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