Duquesne University police searched Fisher Hall Monday night after someone discovered a bomb threat scrawled on a bathroom wall.
University spokeswoman Bridget Fare said the threat was discovered in a sixth-floor women's rest room about 8 p.m. School police evacuated the building as a precaution and began searching.
They had not found anything as of 9:45 p.m., when the building remained closed.
Ms. Fare said several classes were being held tonight in the building, which is home to the School of Nursing, some labs and modern languages courses, among others.