LE MARS, Iowa (AP) — A judge has found a northwest Iowa man guilty of second-degree murder for killing his sister more than 2½ years ago. Judge Jeffrey Neary said Friday in Plymouth County District Court that 36-year-old Thomas Bibler was under the influence of a sleeping aid when he stabbed to death Shannon Bogh outside her home in Le Mars. The judge says that intoxication made Bibler unable to form the specific intent to kill his 27-year-old sister. Intent is one of the elements required for a first-degree murder conviction. Neary had presided over the nonjury trial . Bibler is scheduled to be sentenced Feb. 22.