PRESCOTT VALLEY, Ariz. — On Monday at approximately 4:30 a.m., Prescott Valley Police responded to a call of criminal damage at the Humboldt Unified School District bus facility, according to a press release from the police department.

Officers learned that unknown suspects caused damage to approximately 83 school buses, rendering them unable to be used. The damage was not believed to be permanent but did require a time intensive repair process, according to the release.

Employees discovered damaged buses with "2015" painted on their windows Monday morning, according to The Arizona Republic. The bus’ tires were deflated and the valve stems were removed, police told the newspaper. Lt. Brandon Bonney, a spokesman for the police department, told The Arizona Republic tow trucks had to be used to repair the tires.

The buses could not be driven until repairs were made, causing problems with the district's morning pickup schedule. The initial estimate to repair the vehicles is approximately $3,500, the press release stated. At this time, police are not commenting on the specific damage caused as the investigation is ongoing.

There have been indications that this act may have been perpetrated as a senior prank, but this is not verified, the police department said. The incident is being investigated as a felony.

Alternate transportation arrangements had to be made for several hundred children, and field trips had to be canceled.

Bus runs were not back on schedule until mid-day, according to an announcement from the district.

This news follows a similar story from earlier this week of an apparent senior prank at Northwestern Local Schools in Springfield, Ohio.