GUILDERLAND — An administrator was emailed Monday evening, warning that a bomb would go off at Guilderland High School on Tuesday, Principal Thomas Lutsic wrote in an email to parents Monday night.

The email came from a student’s account, said Aubrey Kammler, the school district’s communications specialist. Investigators are now looking into who was responsible — the student whose name was on the account or someone else who might have obtained the password, said Marie Wiles, district superintendent.

At 9:30 p.m. on Monday, local police inspected the building with a police dog, and the high school building was deemed safe, then locked down for the night, the principal wrote.

Administrators conducted another walk-through Tuesday morning, with police, before the start of the school day, Kammler said.

Increased police presence at the high school on Tuesday was a “precautionary measure,” Lutsic wrote.

The school district gets about one bomb threat a year, Wiles said. In her experience, she said, the motivation has usually been “kind of a joke, and a way to interrupt the school day, cancel some classes.”

Asked about what kind of punishment might await the student who made the threat, Wiles said there were two parallel tracks. One would be the school disciplinary action, which the school would control and which “would likely go to a superintendent’s hearing,” and the other a separate process to be handled by law enforcement.