Check with the landowner to see if they had permission. If they did, ask why and request a portion of the lease money to be returned. The authorities should have been called when the violation occurred. However, did they field dress the bear on the property? If so, there is evidence of a kill, and your friend is a witness. The authorities should still be able to make the case. It sounds like you may need to press this further in the right way with the authorities. You need to address this now, or the problem will just get worse. Always have a witness with you for your protection.