The San Francisco Police Department called off its search for a bomb about three hours after a threat was reported at a high school today.

The bomb threat at Archbishop Riordan High School, located at 175 Phelan Ave., was called in at 11:13 a.m., Officer Carlos Manfredi said. Officers stopped their search at about 2 p.m.

Nothing was found, Manfredi said. Some Muni buses in the area had being redirected during the search. Bishop Riordan High School is the city's oldest all-male high school.

More information about the school can be found on its website: http://www.riordanhs.org/