PAWHUSKA, Oklahoma - Pawhuska Police say they are investigating the third threat in a week at Pawhuska Public Schools. This time, a substitute teacher was arrested, according to Chief of Police Nick Silva.

Silva said they were notified by the school just before 1:30 p.m. Thursday that a substitute named Nancysu Herron had threatened to kill a student.

"Another staff member was alerted by a student, and the school responded quickly by alerting the police department," Silva said in a news release.

"Ms. Herron was placed under arrest immediately by our School Resource Officer after a written and verbal statement was given by Ms. Herron admitting she had threatened to kill one of the students."

Justin Boone, 20, was arrested August 20 after police said he threatened to shoot up the school and burn down his place of employment.

On August 28, a juvenile female student threatened the school, Silva said. That girl is now in custody of the state, he said.

"The partnership between the Schools and Police Department has only strengthened to help ensure the safety of our students and staff," the chief said.

Records show Herron has a court hearing set for Friday.