Officers went to the PNC Bank in Montgomery Township on Thursday night after an alarm went off. They saw what they thought was at least one person through the windows of the bank, which had its blinds drawn.
The area was sealed off and three nearby apartment buildings were evacuated as a precaution. Meanwhile, authorities used bullhorns and made telephone calls in a bid to make contact with whoever might be in the bank.
After repeatedly failing to get a response, a SWAT team entered the building and discovered the cardboard figure.
It was not immediately clear what set off the bank alarm.