Bounty manager is not responsible if the project turn to become fraud project. But bounty manager need to assest the project and the team. They also getting paid for being a bounty manager. They need to do verification. Not only token will be paid or not but whole project.
If a fraudulent promotion is considered criminal, then the closest to the accusation (other than the project team) is the bounty manager if it has received payment. I will assume the manager's bounty has done research and is in charge of the promotion after receiving the contract approval.
However, sometimes the actual situation is different and the outcome is unpredictable. So it is not easy to say that anyone who has been involved in a scam project is considered a criminal without an intensive examination.