Princeton police are investigating a bank robbery around 8:40 a.m. this morning at Planters Bank, 208 N. Jefferson St. Shortly after the bank opened, a man wearing a mask walked into the bank and showed a teller a gun. He demanded money and ordered some bank employees into the vault. He left the bank in a newer dark-colored model car with shiny wheels. There were no injuries. The bank is closed for today. Police are in the process of reviewing surveillance cameras as the investigation continues.