Update: The suspicious powder was flour. The Liberty Bell Center and part of one street next to it have been evacuated after a guard found the balloon inside the visitors entrance to the Liberty Bell Center around 2:30 p.m. Thursday.
FBI spokesman J.J. Klaver says testing is being done on the substance. He says it's not explosive or radioactive, but it is what he called a “biological substance.”
“It appears to be some type of balloon that had powdery substance inside of it. He (guard) picked it up, put it in a plastic bag to secure,” Klaver said.