A student was found with weapons at Madison High School early Monday morning and is now in custody, NEISD spokeswoman Aubrey Chancellor said.
The campus was placed on lockdown after 10 a.m. while authorities conducted an investigation. The lockdown was lifted shortly before noon.
Chancellor said the unnamed suspect had brought three loaded guns and a knife to school. The student is 17-years-old.
NEISD officials said the student will be charged as an adult for a terroristic threat and for possession of guns in a prohibited area.
The student had been reported as a runaway by parents. They came to school and met with their child and administrators.
NEISD officials said the parents requested that administrators search his backpack, where they allegedly found two guns, a knife and additional magazines of ammunition. Officials said the student admitted to hiding an AK-47 in the restroom, too.
The student said he had planned to make some demands on the school's public address speakers.
The student did tell police officers that it was his intention that he was going to come over the announcement the intercom system at the school and that he was going to make a list of demands he said if those demands were not met then he would act, Chancellor said.
All of the weapons and ammunition were recovered.
It appears that this person acted alone and there is no reason to believe that there are any other suspects, Chancellor said.
This news comes on the heels of a week-long threat via email last week at all San Antonio schools.