San Jose Police have identified a 12 year-old girl believed to be responsible for sending a threatening tweet earlier this week to the Alum Rock Union School District.
On March 1, the San Jose Police Department's Violent Crimes Enforcement Team served a search warrant at the girl's residence in San Jose.
According to police, the girl was contacted at her residence, but was not taken into custody. The investigation is ongoing.
Several safety measures were taken by the East San Jose school district and San Jose police after a social media shooting threat on Wednesday.
The Alum Rock Union Elementary School District operates 19 elementary schools and seven middle schools in San Jose.
Alum Rock Union Elementary School District officials learned of the tweet that came from an anonymous account detailing distaste for the district as a whole and how they wanted to bring harm to its schools first thing Wednesday morning, Superintendent Hilaria Bauer said.
Bauer called the threat offensive because the person responsible commented how they hated the school district and were happy they were from "a more affluent area," followed by a series of expletives.
There were no specific schools narrowed out in the tweet, which simply stated that the person wanted to "shoot up" all of them.
"This was the ranting and raving of someone who is obviously not mentally stable," Bauer said.
Bauer said that because it was so general, it affected all of the school district's 10,000 students, 600 teachers and 27 sites.
An automated call went out to the district's parents "fairly late" on Wednesday night, Bauer said. She said that she only wanted to report the facts so her office waited until they had more information about the preliminary investigation done that day.
"Although we cannot confirm the credibility of the threat, we are treating it as serious and have contacted the San Jose Police Department," Bauer said in the phone message. "We have filed an official complaint with Twitter requesting they take the appropriate steps to investigate the statement made on their platform."
Bauer said the district's policy is not to send out one of those calls to parents past 9 p.m., but she found the circumstances serious enough to break the rule so that parents could make decisions about sending kids to school.
Bauer did not have a total absence report showing how many parents had opted not to send their kids to school. She said she thought there "were some absences" but could not quote how many.
Bauer visited schools this morning to talk to concerned teachers and parents personally about what the school district and the city's Police Department is doing to ensure campus safety.
What Bauer didn't know would be the "silver lining in the storm" was that parents are now willing to back her decision to lock certain doors at schools that face possible public access.
"In the past, we had some pushback from the community when we keep our doors around campuses locked," Bauer said.
The school district is, as a result of the threat, now moving to pass a resolution where the main office doors will remain unlocked to provide a sense of welcome to the community, but points of entry to rooms commonly occupied by the students will be locked, according to Bauer.
Bauer said the school district will be installing surveillance cameras at all campuses.
Each campus in the district has a resource officer present, but San Jose Police Department officers have also been providing extra patrolling since the threat emerged.
Police said all patrol officers are aware of the ongoing investigation into the threat.
San Jose police did not advise any schools to close, but began an investigation in which detectives are attempting to identify the person responsible for the tweet, police spokeswoman Officer Gina Tepoorten said.
San Jose police also assisted Wednesday at San Jose State University, just over 5 miles from the elementary school district headquarters, after a written shooting threat was found on the walls of a women's bathroom on the third floor of Dudley Moorhead Hall, according to university spokeswoman Pat Harris.