(CNN) -- A Nebraska assistant high school principal died Wednesday night after she was shot by a student who also shot the school's principal, a police spokesman said.

The student, a senior identified by police as Robert Butler Jr., 17, was later found dead of an apparent self-inflicted gunshot wound in his car, Omaha Police Officer Michael Pecha said. Butler had recently transferred to Millard South High School, Pecha said.

Millard South Assistant Principal Vicki Kaspar, 58, was life-flighted to Creighton University Medical Center after the shooting, police said. Principal Curtis Case, 45, was taken to the same hospital, where he is listed in serious but stable condition.

Police Chief Alex Hayes said Butler was the son of an Omaha police detective who had served on the force for seven years. Pecha said detectives were interviewing the elder Butler.