Harsh,
Yes, but you need to follow the due course of law, such as you need to issue a show cause notice, allow the employee to respond in writing, consider the response, warning letters for first misconduct, and then after a repeat of the behaviour, conduct a fully documented inquiry etc and only and then termination. i dont see any mention of a warning for previous misconduct.. that should always be in place before termination.
This is because as a cashier, the employee would most probably be non supervisor, and can challenge the termination. The labour courts are labour friendly (they are meant to protect the employees rights), and will quash any termination not done as per the prescribed procedure.