And the Johnson City Press reports the threats prompted lockdowns in four other school districts: Carter and Washington counties and Elizabethton and Johnson City.
Kingsport City Schools also announced extra precautions.
According to a press release from the Sullivan County Sheriff's Office, an individual used a mobile device to make the post, with investigators unable to locate or identify the user on Wednesday. A geographic location provided by the website where the post was made indicated the vicinity of Bluff City, according to police, but the SCSO said that had yet to be verified.
"Due to the nature of the threat, the Sullivan County Sheriff's Office has taken precautionary measures for the safety and security of the schools in our jurisdiction and we have been in contact with Evelyn Rafalowski, the Director of Sullivan County Schools," the SCSO press release stated. "Mrs. Rafalowski has implemented a 'soft lockdown' at all schools, out of an abundance of caution."
Rafalowski said the school system implemented the soft lockdown when it received the information from the sheriff's office.
"It’s a precautionary step on our part. Nothing has come to us indicating that it's one of our schools," Rafalowski stressed.
"From what we understand, the cell phone pinged a tower in Bluff City, Tennessee, and it could be coming from Carter, Washington or Sullivan County. There's no way of tracking the cell phone or where the person is or was, or if this person is even in one of our buildings," she explained.
The school system alerted parents of the county-wide soft lockdown through its School Messenger system. The soft lockdown remained in place at all levels for the remainder of the day.
Police say the post included "threats to kill himself and others at a school," but the threats were non-specific in nature and did not identify a specific target. All surrounding jurisdictions were advised of the threat.
Kingsport City Schools alerted parents that it was working with the Kingsport Police Department to have additional police presence around schools throughout the afternoon.
“...We have no indication or reason to believe that Kingsport City Schools was specifically involved, but out of abundance of caution, students were brought inside today when we were made aware of the situation. School operations are continuing and dismissal will take place as normal, with an increased Kingsport Police Department presence,” the system said on its Facebook page.
An investigation is continuing.