A trio of Louisville teenagers has been arrested and charged with plotting the death of a middle school student.

Louisville police spokesman Phil Russell says detectives began investigating after a call from authorities at a middle school in eastern Jefferson County, who reported that there was word of a plot by some students to kill a fellow student.

Russell says three people had been working since March to plan the murder of a 13-year-old girl.

Police arrested two girls, ages 13 and 14, on Tuesday and charged them with conspiracy to commit murder. Neither has been named because of their age. Seth Ryan Woods, 19, of Louisville, also was arrested on the same murder conspiracy charge.

Russell said the teens had planned to execute their plan by this weekend.