It wasn't until January 2016 that Facebook received the signed certification from Cambridge Analytica CEO Alexander Nix, claiming they had deleted the data related to 87 million Facebook users, TechCrunch reported on Friday.
The Facebook users' data was improperly obtained in 2014 by researchers with access to Facebook's developer platform.
Kaiser, a former employee of the now defunct British data analytics and consulting company Cambridge Analytica, revealed the documents at the WorldWebForum conference in Zurich.
This 'email exchange' - which TechCrunch has not been able to independently verify at this point - has never previously been published.
Earlier this month, new details leaked by Kaiser via an anonymous Twitter account, @HindsightFiles, showed the extent of the rot is far deeper than previously thought.
"Over the past two years I have given evidence to investigators, journalists and academics to analyse what happened at Cambridge Analytica, and how our data was used to influence democracies around the world. In the name of shedding light on these dark practices, I am releasing documents and emails in full for the public good," Kaiser, who worked with Cambridge Analytica from 2014 to 208, was quoted as saying.
Over the next months, more than 100,000 documents relating to work in 68 countries are set to be released, according to a report in The Guardian.
Facebook CEO Mark Zuckerburg has apologized for having failed to check that Cambridge Analytica had deleted the information.
"When we heard back from Cambridge Analytica that they had told us that they weren't using the data and deleted it, we consider it a closed case. In retrospect, that was clearly a mistake. We shouldn't have taken their word for it. We've updated our policy to make sure we don't make that mistake again," Zuckerburg said during Washington Senate hearings into the scandal.
According to Kaiser, the Facebook data scandal was part of a much bigger global operation designed to manipulate people in collaboration with governments, intelligence agencies, commercial companies and political campaigns.
( With inputs from IANS )