FBI: Carrier IQ files used for “law enforcement purposes”

A recent FOIA request to the Federal Bureau of Investigation for "manuals, documents or other written guidance used to access or analyze data gathered by programs developed or deployed by Carrier IQ" was met with a telling denial. In it, the FBI stated it did have responsive documents - but they were exempt under a provision that covers materials that, if disclosed, might reasonably interfere with an ongoing investigation.