This articlewas producedwith support from WIRED.Last year, a joint investigation revealed that a Florida-based data broker, Datastream Group, was selling highly sensitive location data that tracked United States military and intelligence personnel overseas. However, at the time, the origin of that data remained unknown.Now, a letter sent to US senator Ron Wydens office that was obtained by an international collective of media outletsincluding WIRED and 404 Mediareveals that Eskimi, a little-known Lithuanian adtech company, was the ultimate source of that data.Eskimis role highlights the opaque and interconnected nature of the location data industry: A Lithuanian company provided data on US military personnel in Germany to a databroker in Florida, which could then theoretically sell that data to essentially anyone.