The Mercedes Independent School District is investigating social media threats made towards Sgt. Harrell Middle School on Monday.

District officials said upon learning of the threat, campus administration immediately called for a shelter in place and the district launched an investigation into the matter.

"The safety of students and staff is our main priority. All threats to our school or students are taken seriously and investigated thoroughly," a news release stated. "We will continue to take all measures necessary to maintain a safe and secure environment at all campuses."