I have a boss who steals invoices and put his name on the sales sheet for the commission....?

He's in a istant manager position and I've had discussions with the store manager to address my concerns, but was ignored because he's a high volume writer. Is there any law that I could use in reference to stealing from other emplyers as such as "quid pro quo"? Its not a form of ual harments, but he's using his position of employment for financial gain by stealing other invoices and forgering the doents.