"The Electronic Surveillance System (ELSUR) is owned by U.S. Immigration and Customs Enforcement (ICE), a component agency within the Department of Homeland Security (DHS). ELSUR allows ICE to track and search for ICE applications for court orders that authorize ICE to intercept oral, wire, or electronic communications during the course of a criminal investigation. ICE conducted this Privacy Impact Assessment (PIA) because ELSUR contains personally identifiable information (PII) and to publicly document the privacy protections that are in place."
United States. Dept. of Homeland Security: http://www.dhs.gov/