GARDEN GROVE, Calif. (KABC) -- Bolsa Grande High School, located at 9401 Westminster Avenue, was locked down for almost two hours due to a bomb threat before police cleared the school Tuesday afternoon. No threat was found on campus.A note threatening there was a bomb on campus was discovered by a student in or near classroom number 318 at about 1:45 p.m. The student reported the note to staff, and the lockdown was quickly implemented, according to Garden Grove Police Lt. Ben Stauffer.Garden Grove Police searched the campus and declared there was no bomb or threat at about 3:50 p.m.Rooms were evacuated one by one, and students were taken to the adjacent city park, where a head count of students was performed.Parents were allowed to pick up some students at Atlantis Park. Students who drove cars or rode bikes to school, or who wanted to retrieve items from the school, were allowed back onto campus shortly before 4 p.m.Tuesday's bomb threat follows a three-alarm fire on Sunday afternoon that damaged eight Bolsa Grande High classrooms There was no way to connect the threat to Sunday's fire, said Garden Grove Police Lt. Ben Stauffer.The cause of Sunday's fire remained under investigation. It was not immediately known if the fire was deliberately set.