A threat made against Ames High School was determined not to be credible, according to the Ames Community School District.

The threat — the exact nature of which authorities have not specified — still rattled parents, based on chatter on social media. District spokesperson Amy DeLashmutt said the Ames Police Department received the threat against the high school just before 11:15 a.m. Monday.

The district issued a shelter-in-place notice for the high school and limited entry and exit into and out of the building.

Officers responded, and the shelter-in-place notice at the high school was lifted around 1 p.m. after police and school officials determined the threat was not credible, DeLashmutt said.

The police department maintained a presence at the school the rest of the day. And "the school is utilizing increased supervision of exterior doors" — measures taken "out of an abundance of caution," DeLashmutt added.

She said police would continue to investigate the incident.

Ames Police Department spokesperson Sgt. Amber Christian said "preliminary information has indicated the phone number was spoofed from a voice over internet phone call."

"We are continuing to look for the source of the call but it is undetermined at this time," she said.

Christian added the school's request for increased officer presence was only through the end of the day on Monday. But police regularly provide extra patrols to all schools as available, she said.

Threats against local schools are not unheard of but even rumors of threats cause concern among families and prompt school and police responses given the extensive history of violence at and against schools across the U.S.

School officials and police officers determined rumors of a threat at Ames High School in December 2021 were unfounded.

Extra police were placed at Ames High School in October 2018 after an anonymous threat from out-of-state was made over a weekend. It was determined that threat did not present any real danger.

Also in December 2021, rumors of nationwide school shooting threats spread on social media. Threats were determined not credible, but they aligned with a significant number of students absent from schools across Iowa.

Phillip Sitter covers education for the Ames Tribune, including Iowa State University and PreK-12 schools in Ames and elsewhere in Story County. Phillip can be reached via email at psitter@gannett.com. He is on Twitter @pslifeisabeauty.

This article originally appeared on Ames Tribune: Officials say threat against Ames High School Monday was not credible