You could sue the employee for stealing your wallet (you could also press charges against him or her, since theft is a crime as well as grounds for a lawsuit), but would most likely not be able to sue the store. An employer is only liable, under the theory of respondeat superior ("let the master answer"), when the employee commits a wrong in the course of his/her employment, which does *not* just mean during work hours or while at work--it means a wrong that was part of his/her job responsibilities. It is not part of an employee's responsibilities to steal from customers; employers are very, very rarely held liable for the deliberate criminal acts of employees, since such acts are considered outside the scope of employment.