Department of Homeland Security recently rolled out an on-line tool to check the status of a Freedom of Information Act request.
The Freedom of Information Act (FOIA) allows the public to request government documents. In the immigration context, this is usually to do with an applicant’s records. The government is supposed to produce relevant documents that can be released without compromising certain legitimate government interests. In some cases, requestors must pay for copies produced.
More information regarding FOIA for DHS may be found here. DHS contains the three primary immigration agencies: U.S. Citizenship & Immigration Services, U.S. Immigration & Customs Enforcement, and U.S. Customs & Border Protection.