The Sahuarita Unified School District (SUSD) announced the closure of all their schools after numerous posts appeared on social media in the space of 24 hours.

In a letter to parents, the district said threats were made against three schools on Monday—Sahuarita High School, Walden Grove High School, and Anza Trail School—as well as an additional threat to Sahuarita Middle School posted at approximately 4:30 p.m. the same day.

The district said due to “the nature of the threats, and in an abundance of caution,” all SUSD schools will be closed Tuesday, as well as the Early Childhood Center, its L.I.N.K. program and after school activities for grades K-8.

All other high school after-school activities will be evaluated on a case-by-case basis at the schools.

SUSD said they anticipate that the schools will be open as usual on Wednesday.

Prior to the announcement of the closures, detectives from the Sahuarita Police Department said they have not found a “credible and actionable threat.”

“We continue to work and share information with SUSD and other law enforcement agencies. Information has been officially requested from different Social Media companies. Some of the information has been received and we will continue to work with these companies.” the force added in a statement.

Parents of the students described their concern at the potential threat.

“It’s really scary to hear about but you also hear more about them because of social media these days,” Cathy Karnes, whose child goes to Sahuarita High School, told KOVA. “So I always tell my kids to take them seriously and to be vigilant.”

The letter to the parents adds: “Sahuarita Unified School District and Sahuarita Police Department want to make it clear that those who participate in threatening behavior may be prosecuted.

“Additionally, students involved in making online threats are subject to school discipline, including suspension and/or expulsion. Please take a moment to speak with your child(ren) tonight about the seriousness of these incidents. If they see or hear something concerning, they should report it immediately.

“We are grateful for the trust you place with us everyday, and we will always strive to honor that trust in our daily actions.”

Anyone that has information about the alleged threats against the schools has been asked to make a report to the SPD tip line, 344-7847, 88CRIME, or 911.