LOCKHART, Texas (KXAN) — Lockhart ISD said three female students and a male student were arrested after a threat was written on the wall in a girls’ bathroom on the campus Monday morning.

The district contacted police about the girls’ probable connection to the threat, Lockhart Superintendent Mark Estrada said in an email. Estrada said they will face the “maximum consequences within the school district’s authority.” One of the girls is 16 years old, and the two others are 15.

Previously, on Monday afternoon, the Lockhart Police Department had arrested a 16-year-old boy in connection to the threat. Police said he could potentially face terroristic threat charges, which would be a felony.

The threat also circulated on social media. The district did not say what was in the threat or when the district was made aware of the threat.

The district said both Lockhart Police and the Caldwell County Sheriff’s Office would increase their presence around district campuses Monday.

“The Lockhart Police Department takes these threats very seriously,” said Lockhart Police Chief Ernest Pedraza. “The safety and security of our students are paramount, not only to us, but the rest of our community. We spared no time, nor manpower, to ensure classes at Lockhart ISD continued without incident.”

“If you are looking to threaten any of our schools, be prepared to face the consequences,” Pedraza added.

Lockhart ISD encouraged students, staff, parents and members of the community to report any security concerns to their school, the district or the Alert LISD section of the district’s website. The ISD is also reminding parents, staff and students of a community reporting system called iWatch that anyone can use to report suspicious activities.