ONTARIO, Ore. (AP) — A California man who forced a commercial truck to a stop in eastern Oregon by ramming its diesel tanks and then stabbed the driver multiple times has pleaded guilty except for insanity to attempted murder.

The Argus Observer reports 28-year-old Dustin Leroy Rotter of Modesto entered the plea in Malheur County Circuit Court. Rotter attacked 63-year-old Charles VanZante of Jerome, Idaho, last summer on Interstate 84 west of Ontario, Oregon.

Rotter was then released from jail into the custody of the Oregon State Mental Hospital for the next 20 years. Investigators say two doctors found Rotter was guilty but insane. He has a history of mental illness and of not taking his medication.