SAN FRANCISCO (AP) — The California Supreme Court on Wednesday upheld the death penalty of a high school dropout convicted of going on a murderous rampage through his former Northern California school in 1992.

The court unanimously ruled that Eric Houston received a fair trial in 1993. The court also said that there was overwhelming evidence he planned the killings, which supported his first-degree murder convictions.

Houston ultimately killed three students and a teacher and injured 10 more during the rampage and the eight-hour siege afterward at a school about 40 miles north of Sacramento.

Houston was a 20-year-old dropout of Lindhurst High School in Yuba County when he walked into the school on the afternoon of May 1, 1992, with a 12-gauge shotgun in his hand, a sawed-off .22-caliber rifle slung over his back and a grudge.

He was wearing a camouflage vest with pockets full of shotgun shells, two bandoliers full of ammunition, and a full ammunition belt. He had a canteen on his belt. Houston had spent the morning waiting for his unemployment check and then went shopping for shotgun ammunition.

When he arrived at the school in the Olivehurst neighborhood just outside Marysville, he entered the classroom of civics teacher Robert Brens and opened fire, killing the teacher and a student. Brens gave Houston a failing grade in an economics class in 1989. Houston blamed the teacher for his failure to graduate and the loss of a job and a girlfriend.

After leaving Brens' classroom, Houston wandered down the hallway and shot into classrooms along the way. Ultimately, he made his way to an upstairs classroom and ordered the teacher to leave and commanded the two dozen students to blockade the door with a bookshelf. After sending students on several forays throughout the school to roundup other students, Houston took about 80 students hostage in the classroom. He released several throughout the day while negotiating with police.

Houston surrendered to police at about 10 p.m. after receiving a "contract" promising him he would serve no more than five-years in a minimum-security prison.