Investigators have tracked the online threats that led to the lockdown of Minneapolis and St. Paul schools to a computer server in Australia.
St. Paul police spokesman Paul Schnell says the department has notified the FBI and Interpol, but added that authorities do not believe the threats were credible.
Classes will resume as normal on Thursday.
"There is nothing at this point in time that indicates that the threats that were received were credible," Schnell said on Wednesday evening. "But obviously, given the circumstances, both the police and schools will certainly have heightened awareness."
Police in both cities report getting electronic threats of violence this morning, which led to the lockdown of all Minneapolis police schools, along with the Catholic Cretin-Derham Hill High School in St. Paul. Police remained at schools throughout the day, but there were no actual incidents.
Schnell said all the threats have been tracked to the same computer server, but said that authorities have not identified any suspects.
Word first went out this morning, when thousands of parents and guardians of Minneapolis students checked their voicemail and heard an automated message from district spokesman Stan Alleyne.
"Effective immediately, all schools have been placed in a 'code yellow' lockdown until further notice. On lockdown, instruction continues as usual but students remain in their classrooms and outside access to buildings is limited," the message said.
Officials say that message was prompted by a call this morning to the city's 311 phone line, which claimed that someone would come to a Minneapolis school within two hours and shoot it up. The investigation which followed that phone call soon found threats posted on the Facebook and MySpace social networking sites.
Minneapolis Police spokesman Jesse Garcia said no specific school was named, so all 60 public schools in the city went on alert.
While that happened in Minneapolis, officials at Cretin-Derham Hall High School received an email alerting them to a threat posted online. Schnell said the threat was posted on an unnamed Web site. In response, St. Paul police ramped up security at the school, but no incidents occurred.
The only school in the St. Paul public school district affected was Expo Magnet, which was locked down briefly because the school is close to Cretin-Derham Hall.