Police are investigating a bomb threat at Port Jervis High School Thursday.

The bomb threat was called into the Port Jervis Police Department when students were arriving to class. Word of the threat was not received in time to cancel classes. Police kept all the students and staff out of the building until a thorough search was completed.

A room-by room search was conducted by police using bomb-sniffing dogs. No bomb or explosive materials were found. At approximately 8:30 a.m., the police declared the building safe and authorized the district to reopen the high school.

As an added safety measure, officials searched the backpacks and other personal belongings of everyone as they entered the building. Police also guarded the perimeter of the school all day.

School officials and police are chalking up the threat as a prank by a student. However, they are not taking the investigation lightly. Police say they have a few leads, and the principal says the district will prosecute the person responsible to the fullest extent of the law.