His name and face are not revealed because he is a minor.
The boy was reportedly arrested on Sunday for allegedly posting a photo on Instagram of a high-caliber firearm with several names of San Antonio-area schools and future dates in September.
The post mentioned San Antonio Independent School District-affiliated schools, prompting an investigation of the threats.
In a statement sent to KSAT, the district deemed the threats to be not credible.
"We are aware of online activity circulating among schools in local school districts, including SAISD, that has caused concern. Our SAISD Police Department investigated this activity in collaboration with area law enforcement, including SAPD, and at this time, it is determined not to be a credible threat," the statement said.
According to officials, San Antonio police and the Texas Rangers tracked the 12-year-old down and arrested him.
On Wednesday, the boy attended his first court hearing since being arrested over the weekend.
"I feel he's not a danger to myself or anyone," the boy's mother reportedly said to the judge. "The first altercation, he was joking with another student. I did reprimand him and told him not to joke in any manner with any friends. I haven't had any other issues."
KSAT reported that a decision was made about whether or not the boy would be released on probation before his next hearing.
The boy's attorney argued that there was bullying involved, but the state and the probation department said continued detention was necessary, given the child's history.
"There have been some similar incidents to the allegations before the court, judge. Last school year, he was caught on campus with a bulletproof vest. And in April of 2023, he was sent to his alternative campus for a threat made against a school," a member of the probation department said.
"When the search warrant was executed, two tactical vests were found in the home. He sent multiple pictures of firearms to the person he told he was going to shoot up the school," the state prosecutor said.
According to the news station, the boy's mother insisted that her son doesn't have access to firearms. She said he likes camouflage and tactical gear because he wants to join the military and is "a military fanatic."
"This is serious," the judge said. "Joke or not, there are different ways to handle this. If you're having bullies at school, you talk to mom, you talk to school, talk to somebody, but this is not the way to handle this."
The boy was ordered to remain detained and the judge scheduled the next detention hearing on Sept. 25 at 9:30 a.m.