SIOUX CITY | Police and the FBI are continuing to investigate the source of an automated bomb threat Wednesday to the Sioux City school district, which prompted authorities to lock down every school for nearly an hour.
The recorded call, which the district's administrative office downtown received about 8:22 a.m., warned that explosive devices had been placed at the more than 20 school buildings. The caller also said each school would be attacked with rifles within 30 minutes.
The lock down was lifted at 9:15 a.m. after Sioux City police deemed the threat was not credible.
Lt. Mark Kirkpatrick said the call is believed to have been a recorded voice, similar to recent robocalls received by school districts in the U.S.
Associate superintendent Kim Buryanek said the school district initiated their disaster response plan and cooperated with police.
Some parents may have received a delayed phone notification about the Wednesday incident, Buryanek added. The district had to record the message and then translate it into other languages.
Buryanek said the school officials initiated the notification system at 9:39 a.m., more than an hour after the threat was called into the district.
She added some parents may not have received the message if they do not have a current phone number with the school district.
"We take student and staff safety very seriously," Buryanek said. "We take all steps to ensure people's safety."
In western Iowa, the Council Bluffs Community School District also received a similar phone threat Wednesday.
Diane Ostrowski, chief communications officer for district, said the threat did not appear to be automated. The threat was received by an office receptionist between 8 a.m. and 8:30 a.m.
The district was placed on lockout, meaning no one can enter or exit a school building, Ostrowski said. The lockout was lifted at 9:15 a.m.
According to an email sent to parents about 9:55 a.m., some of the district's schools were not in session. The threat was deemed not credible.