The Tulsa County Sheriff's Office added extra deputies to patrol the hallways of the courthouse after receiving a report of a threat that was called in Tuesday at about 11 a.m.
TCSO said the caller had a male voice and called from an unknown number. The person called the Tulsa County Victim's Witness Center and stated that he "would like to report an act of terror," according to a TCSO news release.
The witness who took the call then told the man he would need to contact the police, and the caller responded, "“We are in danger and we need to leave the building."
The witness told the caller that he was transferring him to 911 and the caller hung up, TCSO said.
TCSO said it then initiated the protocol and began to sweep the courthouse from the top floor to the basement and conducted a perimeter check.
The Tulsa Police Department also brought in their K9 officers who aided in searching the building.
"At this time we have found nothing credible and no reason to evacuate the courthouse," TCSO said.