An explosive and newly partially unsealed court filing alleges that the US Department of Homeland Security built up dossiers on ICE observers—including their photos, license plate numbers, and other information—and stored them in a system called the Investigative Case Management database, which was built by Palantir.Palantir did not immediately respond to requests for comment.A spokesperson for DHS calls the case “meritless” and says that “the underlying lawsuit is based on the lie that there is...