One way or another the recruiter is going to find out. But in this situation it seems like very much not your problem. What I would do is accept the job but inf

One way or another the recruiter is going to find out. But in this situation it seems like very much not your problem. What I would do is accept the job but inform the company that while you're not going to go out of your way to inform the recruiter that you're accepting, you are also not willing to lie either. And if the recruiter asks you will be honest about your new employment. That should assuage your own conscious and leave the issue over finders fee where it belongs, with the company and the recruiter.