cnet-declan writes "We already knew the FBI can secretly listen in to car conversations by activating microphones of systems like OnStar. A new Mafia court case suggests that the FBI can do the same thing to cell phones. The judge's opinion and some background information [pdf] are available for reading online. The most disturbing thing? According to the judge, the bug worked even if the phone appeared to be 'powered off.' Anyone up for an open-source handset already?" From the article: "This week, Judge Kaplan in the southern district of New York concluded that the 'roving bugs' were legally permitted to capture hundreds of hours of conversations because the FBI had obtained a court order and alternatives probably wouldn't work. The FBI's 'applications made a sufficient case for electronic surveillance,' Kaplan wrote. 'They indicated that alternative methods of investigation either had failed or were unlikely to produce results, in part because the subjects deliberately avoided government surveillance.'"