An academic who created an app which harvested data from 50 million users says he has been made "a scapegoat" for Facebook and Cambridge Analytica. Dr Aleksandr Kogan completed work for Cambridge Analytica in 2014, but said he had no idea the data would be used to benefit Donald Trump's campaign. The psychology academic said he wanted the data so he could model human behaviour through social media. Facebook says Dr Kogan violated the site's policies. The Cambridge University researcher developed a personality survey called This is Your Digital Life.