I need an advice.

So we have a retail store, and one of the staff members is suspected to be stealing things from the store. Moreover, I am sure that he also keeps some amount from the customer's pay in his pocket and doesn't give full amount to the cash counter.

I know he is really poor, but he always keeps telling us that he has enough money and plots(land). He even has earnings other than the monthly pay, but I'm sure he's lying, ofcourse.

So, what should we do?

1. Fire him??

2. Just be more aware, and let him stay??

3. Tell him that we caught him and give him a chance. (Although I think he'll not change)

4. Others(mention in reply)

Note: Of course, we'll setup CCTV soon, but what he did is not legit, so what's your opinion?