Editor's note: This article has been updated throughout.

A Denison High School freshman was arrested Sunday night after authorities discovered he said planned to bring a firearm to campus on Monday, shoot multiple students and then kill himself.

In a statement released Monday morning, the Denison Independent School District said police were notified of the threat on Sunday night after the 14-year-old male student sent several classmates at least one text message outlining his plans and warning them not to go to school in the morning. The student was subsequently arrested at his home.

“Fortunately, one of the students included in the text alerted Denison Police, who immediately coordinated efforts with Denison High School security officers to quickly identify and locate the student,” the release said. “The student was immediately arrested by Denison police officials, charged with a felony terroristic threat, and ultimately detained in the Grayson County Juvenile Detention Center.”

Denison ISD Superintendent Henry Scott said he did not know whether the student arrested planned to target specific students in the attack, as he had not seen the message or messages firsthand.

“We are extremely thankful for the student who acted quickly and maturely, and informed police about this situation immediately,” Scott said in the district’s statement. “Our students are taught and encouraged to do this in all instances of threats, and we’re very appreciative that this student was willing to step forward and do what was right and vital for the safety of all our students and staff. We are also very concerned about the mental health of the student who allegedly texted the threat, and we pray that he gets the help he needs.”

Scott said he did not know how credible the student’s threat ultimately was, but said the statements he made had to be taken seriously by both administrators and law enforcement. The longtime superintendent said the district did not notify student’s families of the incident on Monday because the student had been taken into custody and, as a result, did not pose an active threat.

“We didn’t because there was no reason to,” Scott said in a phone interview. “The threat was dealt with. If we had thought there was going to be some kind of threat at the school, we would have done that because the person that made that threat was arrested, incarcerated, we didn’t do that at all.”

Scott said the student would not be allowed back into Denison ISD schools until administrators could be sure that he no longer poses a threat.