Can the FBI request information about library users besides their circulation records and records of their web surfing?
A FISA search warrant can target “any tangible thing,” which can include papers, records, computers with hard drives, and data tapes. Computer sign-in sheets, databases, and back-up versions of your library records that preserve some older data history can be targets. An NSL is limited in its scope and can only be used to obtain subscriber information and transactional records for electronic communications.
