Mercer County spokesman Jeffrey Greenburg announced the closure just before 10 a.m. Monday but says that bomb-sniffing dogs found nothing in a sweep of the building. As a result, the courthouse reopened at 1 p.m.
Authorities said they traced a threatening phone call to Margie Small, of Sharpsville. She was arrested Monday and is facing terroristic threats and harassment charges.
The Blair County courthouse in Hollidaysburg received a similar threat by email on Friday that was determined to be a hoax.