A Harrison High School janitor is facing charges for allegedly calling in a bomb threat Thursday after being fired earlier in the day.

According to officials, the 48-year-old man called in the threat around 11 a.m. to a fellow custodian, who alerted police. Within minutes, authorities were at the scene. Nearly 1,000 students were not allowed to leave their classrooms for hours until dismissal.

Officials said they did not call in bomb-sniffing dogs because they never thought the threat was credible.

"The school didn't let us know what happened,? said senior Adam Rosenthal. "We were all scared, we didn't know what was going on."

Police arrested the suspect at his Larchmont home. He faces a felony terrorist threat charge.

The school was also locked down in October following a nearby robbery. Since then, students have taken part in many emergency drills.