LOS ANGELES — On a spring day at Mount Elden Middle School in Flagstaff, Ariz., the phone rang and a receptionist answered. A computerized female voice was on the line with a disturbing message: ‘‘I can see children. I’m going to kill children!’’
The school immediately went into lockdown. Police searched the building as teachers tried to keep nervous children calm in their classrooms. Worried parents flooded school phone lines. In the end, nothing was found.
It was the fourth threatening call in a month at the 10,000-student school system. After an investigation involving the FBI, detectives found a suspect: a 29-year-old New Yorker who, they say, used a Gmail account with a fake name to call in threats and score ‘‘points’’ in an online game.
‘‘It is very difficult to understand,’’ said Barbara Hickman, superintendent of Flagstaff’s school system. ‘‘It was devastating to my elementary schools. It was frightening.’’
Security experts, law enforcement authorities, and school officials say the episode was part of what appears to be a trend around the nation: hoaxers using proxy servers, virtual private networks, and other high-tech identity-disguising tools to anonymously threaten schools online and trigger a huge police response.
In December, Los Angeles, New York City, and several other school systems got e-mail warnings of a grisly attack. In January, districts in Delaware, Virginia, Massachusetts, New Jersey, and elsewhere received bomb threats phoned in using an electronic voice. No arrests have been made in those cases.
In almost every instance, the threats disrupted the lives of thousands of students.
‘‘These are time-consuming and complex investigations,’’ said Fred Ryan, the police chief in Arlington, Mass., whose department is investigating one of the robotic-voice threats received last month. ‘‘We’re all comparing notes.’’
A number of school threats over the past year are a variant of ‘‘swatting,’’ a practice that began around 2007: A caller falsely reports a crime in progress at an address, causing SWAT teams to rush to the scene, weapons drawn.
Victims of swatting have included celebrities such as Justin Bieber as well as online gamers targeted by rival players.
Increasingly, swatting-type attacks have focused on places such as schools. The goal is to get heavy media attention, said Jonathan Fairtlough of the security consulting firm Knoll.
In many cases, the perpetrator has no direct connection to the schools. At least three suspects arrested over the last year were gamers who met online.
Fairtlough described most swatting perpetrators as juveniles who are ‘‘highly intelligent, socially poorly adjusted.’’
Law enforcement authorities fear a swatting episode could turn tragic, with armed officers rushing in. What also troubles investigators: The same technology used by 14-year-old boys conspiring on Xbox could be appealing to terrorists who might be planning real attacks and want to test how local authorities respond.
No statistics are kept at the federal level to show whether the number of school threats nationwide has increased, though individual school districts and police departments have reported more.
Though the hoaxes rarely lead to federal charges, the FBI increasingly is involved, in part because the cases often involve multiple districts across a wide region or someone making threats from out of state or another country.
The FBI and local police agencies have released little information about some of the recent cases. But court records in the small number of federal cases resulting in arrests shed some light on the perpetrators’ possible motives.
Matthew Tollis, 23, of Wethersfield, Conn., pleaded guilty last year to conspiring with other Xbox Live players in making threats against five schools.
In a letter to a judge, he described how he turned to a group of online friends for protection after being a victim of threats himself. When those friends began calling in hoax threats, he felt obligated to participate, he said.
‘‘As my relationship with these individuals grew, I felt greater loyalty towards them,’’ he wrote.
‘‘I trusted them with some of my deepest secrets and told them things I had not even told my own family.’’
?Police probe new threats against Mass. schools. B3
