Ashley Soose, 27, of Karns City, called in the threat Wednesday afternoon to Chicora Elementary School, about 40 miles north of Pittsburgh, state police said.
Troopers responded and took the man into custody, only to determine he didn't have a weapon. He was released without being charged.
But now Soose is charged with making terroristic threats, reckless endangerment and disorderly conduct. She remained in the Butler County Jail unable to post $50,000 bond Thursday and faces a preliminary hearing Tuesday.
Court records don't list an attorney for Soose, and she doesn't have a phone listed in her name.
A criminal complaint indicates she called the school about 12:15 p.m. claiming her ex-boyfriend was headed there, telling the principal, "I'm barricaded in my house and he is going to come and take my son." The principal ordered the school locked down and called police.
"From the school's side, we reacted appropriately based on what we were told," Karns City School District Superintendent Eric Ritzert said.
Parents were alerted to the threat through an emergency alert system that includes text messages, email and phone calls and, until Wednesday, had been used only to announce weather-related delays and closures, Ritzert said.
