PORTLAND, Ore. (KOIN) – The FBI and local law enforcement are investigating phony threats made at several Oregon schools in the past 24 hours.

The most recent threat happened Wednesday morning at Jefferson High School in Marion County. Officials say a caller reported someone armed with a gun went into the school and started shooting, but it was later determined false.

But investigating false threats is a fairly intensive process, according to authorities, especially when dealing with technology that conceals identity.

The Marion County Sheriff’s Office says they received a report that someone with a gun was opening fire inside Jefferson High around 9:30 a.m. on Wednesday.

Officers from multiple law enforcement agencies responded and entered the building, evacuated it and determined there wasn’t a shooter inside.

However, the identity of who called in the phony report remains unknown while the FBI continues to help investigate.

Kieran Ramsey, the FBI Special Agent in charge, asks that parents talk to their kids about the serious impact of making a false threat.

I’m a parent of school-aged kids myself,” Ramsey said. “I know the stress that this talk causes kids in the school system. I hear about the stress that it causes teachers and staff, and I know that it diverts very valuable, limited resources of law enforcement when we have to go run and make sure that there isn’t a legitimate threat.”

On Tuesday, Oak Creek Elementary was evacuated after someone reported a bomb threat, which was later determined “no legitimate threat.” The Lake Oswego Police Department is still investigating.

The Marion County Sheriff’s Office asks that anyone with information about who was involved in Wednesday’s hoax to contact Detective Schwab at jschwab@co.marion.or.us and or 503-932-6294.

FBI Portland tweeted: “A hoax threat is not a joke. The #FBI and our partners follow up on every tip we receive from the public and analyze and investigate all threats. Call 1-800-CALL-FBI to report this crime.”