EUGENE, Ore. (AP) _ Kip Kinkel abandoned an insanity defense and pleaded guilty today to murdering his parents at home and then killing two classmates in a shooting rampage at Springfield's Thurston High School.

Kinkel's plea to four counts of murder and 25 counts of attempted murder came just three days before a trial that offered a chance to get inside the mind of a school shooter and offer some explanation to the baffling string of similar sprees across the nation.

The 17-year-old could get a life sentence when Circuit Judge Jack Mattison sentences him for the May 1998 attack. He told investigators after his arrest that he had ``no choice'' but to kill after shaming his parents by getting expelled from school.