KNOXVILLE, Tenn. (WATE) — A Heritage High student has been arrested by the Blount County Sheriff’s Office for allegedly making threats against the school.

A female Heritage High Student told the two officers about Snapchat messages sent to her by Delron Thomas, another student, on April 8. According to the sheriff’s office, Thomas, 18, confessed to “thinking/planning on shooting up the school” in the messages. An arrest report said the female student also heard Thomas make several statements about shooting up the school in person.

On Monday, April 11, Heritage High’s SRO spoke with the female student about the message and she gave him screenshots of the messages. After this conversation, the SRO attempted to meet with Thomas at the school, however, Thomas was on a field trip in Chattanooga. According to the arrest report, based on the information and evidence a warrant for Thomas was obtained.

Following the warrant being issued, the sheriff’s office made the decision to go to Chattanooga to arrest Thomas. BCSO said this decision was made “in an effort to prevent a mass casualty event from occurring.”

Thomas was found and placed under arrest around 2:11 p.m. on Monday. According to the arrest report, Thomas admitted to sending the messages. He was booked into Blount County jail. He was charged with threat of mass violence on school property or at school-related activity.

The investigation into this incident is ongoing.