IOWA CITY, Iowa (AP) — A man pleaded guilty Tuesday to the 1974 slaying of a teenage girl at a rural Iowa farmhouse, ending a 40-year effort to hold her killer responsible. Robert "Gene" Pilcher, who was long a suspect in the slaying of 17-year-old Mary Jayne Jones but had maintained his innocence, pleaded guilty to second-degree murder during his second trial in the case in Ottumwa. Under a plea deal, prosecutors dropped a first-degree murder charge, which carries a sentence of life in prison. Hours later, her naked, bruised and bloody body was discovered on a bed in a farmhouse 7 miles away. Pilcher was charged with sodomy and perjury in that case, but investigators could not find evidence linking him to Jones' death.