Student Tanner Rahier was at his desk when several classmates were busted.
"It was kind of weird, they just came in and asked for a few students, and then handcuffed them and they said 'these students won't be returning, they're getting arrested,' and that was that," said Rahier.
A total of 14 kids were arrested. Search warrants were also served at many of their homes, where deputies said they seized all kinds of drugs, including marijuana, Ecstasy and cocaine.
A sheriff's spokesperson told Eyewitness News he hasn't seen an operation like this in Riverside County in more than 20 years.
"I think it sends a message throughout the community that we're not going to tolerate any type of illegal narcotic activity on a school campus, and that people should be aware of that," said Riverside County Sheriff's Sgt. Joe Borja.
The sheriff's department said the operation was quick and quiet, and that all 14 students were taken out of class and arrested within 10 minutes.
"It was very low-key. They knew who they were looking for, they escorted the suspects out of class, no disruption to school activities, no disruption to the campus at all," said Jeff Kaye, director of public safety for the Desert Sands Unified School District.
Whatever students were supposed to be taught Thursday morning, they instead got a lesson in what can happen if you're caught buying or selling drugs on campus.
"Just made them realize it's a stupid idea. If they do it, they're going to get caught," said Rahier.