Commenting to # 12, it's actually required by most companies to close the store down after a robbery to call the police and to prevent the robber from coming back. And in Canada and the US it would be against the law to dock her hours after closing the store due to an extremely stressful situation such as a robbery.
OP, call the labor board, or human ressources and file a complaint.
Anyone saying she deserved it, or similar thoughts, should please go out and work a liquor store in some major city until they get robbed. After you're done having a weapon aimed at your face and your personal items stolen, and when you're done peeing your pants, come back and say the same.
The police report is proof enough that your work environment has become dangerous. Tell your boss to install visible security cameras and to make sure no less than two people are working at any time (especially as a woman working so close to closing), or you will sue him for the wages he docked.