Classes at Boise, Kuna, Caldwell and Nampa high schools were disrupted for a couple hours Thursday following bomb or shooting threats.
The Times-News reported emergency dispatchers got a call from a person who claimed they were planning to enter the Twin Falls Christian Academy and cause physical harm.
All five threat calls came in between 10:50 and 11:54 a.m.
Authorities searched all five facilities and found no threat.
"We are aware that this is happening at schools around the valley and will coordinate with those other agencies in the investigation of this crime," said Caldwell Police Chief Chris Allgood.
About 4:30 p.m. bomb threats were called in to three retail stores on Eagle Road, prompting another round of emergency responses.
The crime of making a bomb threat is a felony a felony, chargeable to juveniles or adults, punishable by up to five years in prison.
Crime Stoppers is offering a $1,000 reward for information leading to the arrest of the person or persons responsible for make the bomb threat calls.
Police are asking anyone with information to call Crime Stoppers at 343-2677.