https://www.cnbc.com/2018/03/28/new-york-times-digital-peter-thiel-employee-helped-cambridge-analytica-before-it-harvested-data.html

As a start-up called Cambridge Analytica sought to harvest the Facebook data of tens of millions of Americans in summer 2014, the company received help from at least one employee at Palantir Technologies, a top Silicon Valley contractor to American spy agencies and the Pentagon.

It was a Palantir employee in London, working closely with the data scientists building Cambridge’s psychological profiling technology, who suggested the scientists create their own app — a mobile-phone-based personality quiz — to gain access to Facebook users’ friend networks, according to documents obtained by The New York Times.