Five Flagstaff Unified School District schools were forced to lock down Tuesday morning after another string of threatening phone calls were placed to the schools.
All five schools were searched and nothing was found, district spokeswoman Karin Eberhard said.
Eberhard said parents with children at the schools were notified of the lockdowns.
“It is unfortunate that these individuals continue to harass and threaten our schools,” Eberhard said.
Three schools also received threating phone calls Monday, forcing lockdowns.
The district was the target of similar threats in the previous school year. A New York man was arrested in connection with the threats in July.
The man told police when he was arrested that he was a "gamer" and the threatening calls were made after losing an online game.
Eberhard said the district was complying with the Flagstaff Police Department and did not want to give the callers notoriety, which may lead to earning points in an online game, therefore encouraging the behavior.