The stabbing suspect who was killed by authorities after he attacked four people on the University of California, Merced, campus Wednesday was mad about being snubbed from a study group, the sheriff announced on Thursday.
Warnke said a two-page handwritten "manifesto" found in 18-year-old Faisal Mohammad's pocket indicated the Santa Clara freshman was angry after being "rejected activities pertaining to the day's events." That anger came before authorities say Mohammad stabbed two students, a staffer and a construction worker who ended up thwarting his plan. The sheriff's office on Thursday afternoon said investigators developed the lead on the possible motive during Mohammad's autopsy.
Both Warnke and the school's chancellor Dorothy Leland the motivation for the attack appeared to be "personal animosity" and not terrorism. Leland added it would be "irresponsible to draw any other conclusion based solely on the ethnicity."
Before the unusual and violent outburst on Wednesday at school, Warnke said Mohammad was on "nobody's radar."
Earlier Thursday, authorities revealed what agents found inside Mohammad's bag: zip-tie handcuffs, clear petroleum jelly often used to make explosives, a night vision scope, a safety hammer often used to break windows and two rolls of duct tape. He had laid out a 24-step plan, including student targets, the sheriff said, and had written out a script of what he planned to say. He even wrote out that he planned to steal an officer's gun, the sheriff said at a late Thursday afternoon news conference.
"His intentions were to go further than he did," Warnke said.
But there was nothing to reveal a dark, criminal past in the student's computer, among the evidence that 20 FBI agents and the Department of Homeland Security combed through after the attack, Warnke said.
Mohammad turned 18 last week and graduated in June from Wilcox High School in Santa Clara.
"He was a quiet student," Santa Clara Unified Jennifer Dericco said at a Thursday news conference. "He wasn't highly involved on campus but he was a good student, he did well academically." She said his "social network was small."
She added that it's "just a shocking tragedy for our community to learn this."
Authorities shot and killed Mohammad after a chaotic morning.
As of Thursday morning, one student remained hospitalized but is expected to recover, the university said. The other was treated and released. School officials said the injured staff member suffered a collapsed lung and was recovering Thursday after successful surgery. Price was also treated for his injuries and released.
The rural central California university, located 120 miles south of Sacramento, opened a decade ago and is the newest college in the University of California system.
The campus is expected to reopen on Friday.
NBC Bay Area's John Zuchelli, Jodi Hernandez and Stephanie Chuang contributed to this report.