By Tom Weber, KWMU/AP
St. Louis, MO – Officials at Rockwood Summit High School in Fenton called off classes Tuesday morning after someone called in a bomb threat.
Francis Howell North High School in St. Charles County was also shut down for the same reason.
Rockwood district spokeswoman Kim Cranston said some students were at the school when an administrator heard the threatening voice mail message.
Nothing was found, but Cranston said students were still sent home.
"We've used our three snow days that were in our school calendar," Cranston said. "We now have to assess what we do about this day - what do we do in terms of student and staff making it up? We take all of this really, really seriously."
Both schools are offering rewards for information that leads to the culprits. More than 1,300 students attend Rockwood Summit; the threat at Francis Howell was not phone in but rather written on a wall.
Also Tuesday, security was tightened at Triad High School in Troy, Ill. On Monday, a bomb threat led officials at Mascoutah High School to cancel classes.