ver the past decade, the US Immigration and Customs Enforcement agency (Ice) has amassed millions of data points that it uses to identify and track its targets – from social media posts to location history and, most recently, tax information.

And there’s been one, multibillion-dollar tech company particularly instrumental in enabling Ice to put all that data to work: Palantir, the data analytics firm co-founded by Peter Thiel, the rightwing mega-donor and tech investor.

For years, little was known about how Ice uses Palantir’s technology. The company has consistently described itself as a “data processor” and says it does not play an active role in any of its customers’ data collection efforts or what clients do with that information.

Now, a cache of internal Ice documents – including hundreds of pages of emails between Ice and Palantir, as well as training manuals, and reports on the use of Palantir products – offer some of the first real-world examples of how Ice has used Palantir in its investigations and during on-the-ground enforcement operations.