A 15-year-old Union School District student is in custody of juvenile authorities after he allegedly posted a threatening photo and video of him with a handgun on the social media messaging app Snapchat.

The post was reported to school officials initially and then immediately to police, officials said.

Police Chief Norman Brune said the post led police to believe the student was threatening to shoot a firearm in the school.

Union police, with assistance from the Franklin County Sheriff’s Department, immediately followed up and located the suspect at his home. The firearm used in the post was located. Brune said the gun belonged to a relative, who had no knowledge it was in possession of the teen.

“We are continuing questioning people to see if anyone else is involved, however, we have no reason to believe there is at this point,” he said.

Superintendent Dr. Steve Weinhold said he is remaining in constant contact with the police and that the schools are safe.

“Anytime there’s a situation it’s great to see students step up and share this with their parents and administrators,” Weinhold said. “The Union Police Department did a wonderful job of handling this immediately,” he said.

Repercussions will be up to juvenile officials, Brune said.

“I’m sure they will do what is best for the juvenile and for the safety of the community,” he added.

Weinhold sent out a phone blast to notify district parents of the incident.

The message was as follows:

“Late Sunday night, the Union R-XI School District was made aware of a potential threat to Union High School that was posted on social media.

“The Union Police Department was immediately notified. The Union Police Department, assisted by Franklin County Sheriff’s Department immediately followed up and located the suspect at their residence.

“At this time, the suspect is in care of juvenile authorities. Moving forward, we will remain in constant communication with local and county officials as the investigation is still ongoing.

“As always, our main priority is the safety and wellbeing of all of our students and staff. At this time, all Union R-XI schools will be in session Tuesday, Jan. 9.”

Missourian Staff Writer Kavahn Mansouri contributed to this article.