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.
Carrier IQ came under fire after a security researcher demonstrated that the previously little-known company had software installed on a variety of phones on a variety of networks that could track user locations, keystrokes, encrypted Internet traffic and more, some of which was or could be sent back to either the cell phone owner's service provider or Carrier IQ's own servers.
What is still unclear is whether the FBI used Carrier IQ's software in its own investigations, whether it is currently investigating Carrier IQ, or whether it is some combination of both - not unlikely given the recent uproar over the practice coupled with the U.S. intelligence communities reliance on third-party vendors. The response would seem to indicate at least the former, since the request was specifically for documents related directly to accessing and analyzing Carrier IQ data.
I plan to appeal the blanket denial in hopes of answering that question.
Here is the full denial of the request: