The incident happened on Friday, when the UCR police department executed a search warrant in a campus residence hall "after evidence of a weapon was found on campus," the school said in a message to students.
Officers searched a room in the North District residential apartments and found an assault rifle registered to a student, ammunition, five high-capacity magazines and "hand-drawn images in a journal depicting a violent act."
The student was suspended and ordered to leave campus. The individual's identity has not been released per privacy rights but the Riverside County District Attorney is evaluating possible criminal charges.