Federal investigators have uncovered up to 27 death penalty cases in which the F.B.I. possibly incorrectly connected defendants to crimes with bad forensic data. The investigations come after a Washington Post report that found that F.B.I. officials knew that sloppy forensic work could have led to convictions of innocent people, but authorities decided not to notify defendants or conduct thorough reexaminations of the cases. The investigation into the convictions by federal authorities follows another high-profile capital punishment controversy, when a Public Defender Service found that the same flawed D.N.A.-matching method was responsible for the wrongful convictions of three men in death penalty cases. All three were later exonerated …
