According to a report in CNET on Friday, internal emails by Facebook Deputy General Counsel Paul Grewal, made available by the Attorney General for the District of Columbia, revealed Facebook was concerned about the "sketchy" Cambridge Analytica in September 2015.
The email correspondence started in September 2015 and ran through February 2016.
The Guardian first reported that Cambridge Analytica was supporting Ted Cruz's campaign using Facebook data through an online quiz. The political research firm later worked on US President Donald Trump's campaign.
"We suspect many of these companies are doing similar types of scraping, the largest and most aggressive on the conservative side being Cambridge Analytica, a sketchy (to say the least) data modelling company that has penetrated our market deeply," read an email dated September 22, 2015.
In a blog post late on Friday, Grewal said that they agree with the District of Columbia Attorney General to jointly make public a September 2015 document in which Facebook employees discuss public data scraping.
"We believe this document has the potential to confuse two different events surrounding our knowledge of Cambridge Analytica. There is no substantively new information in this document and the issues have been previously reported," Grewal defended.
According to him, these are two distinct issues.
"One involved unconfirmed reports of scraping accessing or collecting public data from our products using automated means and the other involved policy violations by Aleksandr Kogan, an app developer who sold user data to Cambridge Analytica," he elaborated.
Facebook said it was not aware that Kogan sold data to Cambridge Analytica until December 2015.
"That is a fact that we have testified to under oath, that we have described to our core regulators, and that we stand by today," said Grewal.
In September 2015, a Facebook employee shared unsubstantiated rumours from a competitor of Cambridge Analytica, which claimed that the data analytics company was scraping public data.
An engineer looked into this concern and was not able to find evidence of data scraping.
According to Facebook, the first indication of Kogan's involvement didn't come until December 2015, three months later.
"Cambridge Analytica was a clear lapse for us, which we have worked hard to address," said Grewal.
Cambridge Analytica harvested data through an app called "thisisyourdigitallife" that offered personality predictions.
The Netflix documentary "The Great Hack" reveals the sordid tale of UK-based and now defunct political consultancy firm Cambridge Analytica and its role in swaying US voters in the 2016 presidential elections which brought Trump to power via illegally accessing data of 87 million Facebook users.
In April 2018, Facebook CEO Mark Zuckerberg testified in front of the US Congress that it learned in 2015 that Cambridge Analytica had bought data from an app developer on Facebook that people had shared it with.
( With inputs from IANS )