NOBLESVILLE, Ind. -- Parents were contacted and school was delayed again Thursday morning in the Noblesville Schools district after someone phoned in a bomb threat to the city's dispatch center.

The call came in at about 7:15 a.m., about 20 minutes before the normal start time at the Noblesville High School and the middle school. The caller did not name a school.

"The buildings were evacuated, and students were kept away from the buildings while the buildings were swept," said Sharon Trisler, the school system's public relations director. "Some students were kept on buses while the buildings were searched."

Teachers and other staff members searched the school district's buildings and didn't find anything of note.

All students were allowed into schools by 9 a.m., after all buildings were deemed safe.

Parents of the district's 2,400 students were told of the incident by phone and e-mail.

Someone phoned in a bomb threat at the same school district on Feb. 12. In that instance, police were called and classes were canceled for the day.

Editor's Note: Bomb threats at schools happen fairly frequently. They are normally not publicized, because in the vast majority of cases, there is no validity to them. 6News and TheIndyChannel.com decided to cover this story because this is the second such disruption at the same school district within a couple of months.