Authorities Friday were investigating a 911 call claiming that a bomb would explode at the Governor's Mansion, which resulted in evacuation from the state Capitol of more than 1,000 people, including more than 500 schoolchildren who were there for a special event.
No arrests were made as of late Friday, although the Oklahoma Highway Patrol initially said a woman had been taken into custody.
No injuries were reported.
A woman called Oklahoma City's 911 emergency line at 10:25 a.m. Friday and said a bomb would explode in five minutes in the Governor's Mansion and another building, patrol trooper Betsy Randolph said.
Gov. Mary Fallin, who was in her Capitol office, ordered the Capitol to be evacuated as she was being escorted out of the building.
More than 500 fifth-graders from across the state, dressed in colonial attire, were in the Capitol taking part in the annual Colonial Day, a study in the history, culture and personalities of 18th-century America.
People were allowed back into the Capitol about an hour later. Most stood outside in chilly weather; some of the nearly 600 Capitol employees went to their vehicles.
Doug Kellogg, the Capitol's building manager, and Joel Kintsel, parliamentarian and administrator of the House of Representatives, ushered about 300 of the youngsters and their parents and teachers out of the cold into the auditorium of the Sequoyah Building near the north plaza of the Capitol.
Law officers talked to the woman whose name was given as the 911 caller, but determined she didn't make the call, Randolph said.
Before investigators cleared the woman, it was misunderstood that a suspect in the bomb hoax was in custody, Randolph said.
Students respond well
During the evacuation, a few of the Colonial Day presenters, dressed as George Washington and other colonial characters, gave their talks and presentations on the Capitol lawns.