Whistleblower Christopher Wylie, who helped set up data analytics firm Cambridge Analytica, said on Tuesday (March 20) that he believed the company had developed techniques capable of having an impact on elections.
Speaking at a press club event in London, Wylie said he regretted working for the firm and apologised for what he described as his "incredibly fundamental role" in setting up the company.
Cambridge Analytica harvested private information from more than 50 million Facebook users in developing techniques to support President Donald Trump's 2016 election campaign, the New York Times and London's Observer reported on Saturday (March 18).
The firm's chief executive Alexander Nix was suspended after a secretly recorded video emerged in which he said that his UK-based political consultancy's online campaign played a decisive role in Trump's victory.
Wylie said working with Nix felt liberating as it enabled him to work freely on his research about predicting political behaviour using psychometric data. But he said the environment at the company soon became "toxic".
Facebook's shares fell for a second day, closing down 2.5 percent to $168.15, as investors worried that its dealings with Cambridge Analytica might damage its reputation, deter advertisers and invite restrictive regulation. The company has lost $60 billion of its stock market value over the last two days.
U.S. and European lawmakers have demanded an explanation of how Cambridge Analytica gained access to user data in 2014 and why Facebook failed to inform its users, raising broader industry questions about consumer privacy.