When a worker is not on the payroll or does not have a direct relation, it is indeed very difficult to take action against such an employee. However, in the interest of the organization, the contractor is surely connected to the organization; thus, the employee can be held accountable for any violation or infringement of rules and regulations. The contractor with whom the worker is associated may be advised to take necessary action accordingly in this case. Furthermore, the company may proceed to file a Police Complaint against the worker, depending on the gravity of the offense, with information provided to the contractor. The affected party should take steps by reporting the incident to the organization, enabling the organization to promptly intervene in the interest of both the affected party and the organization for further action.
Best of luck...