A substitute teacher at Aliso Niguel High School in Aliso Viejo is facing a criminal charge after he allegedly made a threat in the classroom Wednesday afternoon, causing a school-wide lockdown.

The teacher, 69-year-old James Setterholm, was arrested for making criminal threats, the Orange County Sheriff’s Department said.

A student told KTLA the teacher was upset about students leaving the class too often to use the restroom and for other reasons.

A student who told KTLA his name is Gary Winthorp characterized the threat as something akin to, “I’m so mad I’m ready to kill you guys.”

“We all kind of freaked out,” he said. “It’s kind of scary being told that by your teacher.”

The threat was reported to authorities at about 12:20 p.m., and the school was ordered to shelter in place, according to Jimmy Knodel, spokesperson for the Capistrano Unified School District.

“I was in my math class and we got it over the PA,” said student Luke Avery. “They said, ‘shelter in place,’ and then maybe 10 seconds after that, they said, ‘This is not a drill.'”

The shelter-in-place order was lifted at 1:12 p.m.