ROCKDALE, Texas (KXAN) — Rockdale ISD was put on a temporary lockout after a student at Rockdale Junior High sent a threat to several other students’ phones on Tuesday afternoon.

According to Rockdale ISD, the threat was sent via an air-dropped image during the lunch period. The students shared the message with campus administrators, who then contacted district administration.

All Rockdale ISD campuses were placed on “secure lockout” to ensure no one could enter or exit the building as police investigated the threat.

After police concluded their investigation, the lockout was lifted.

“The police responded to our call immediately and began making a plan to identify the students involved. Our students were all very cooperative which allowed the police and administration to complete the investigation as quickly as possible,” the school district stated.

Information about the contents of the threat has not been released.

All information about the incident has been turned over to the Rockdale Police Department to complete a criminal investigation.