Photocopy the grad. student's paper--you seem to be in possession of it. Send it via snail mail to said reviewer with a little note, but without a return address. Don't fax. He can trace you that way.
I know this is an ugly case. I was upset when I first found out about it a few years ago and hoped that she would not go as far as publishing it in a book. She probably did it out of desperation, since her dissertation from a decade ago was terrible and she needed a quick substitute to get a tenure. Hence, she grabbed other people's work(s) and got it into print. If I inform this to the critical reviewer, I am sure he can do something, given that he is an outspoken (almost combative) person and doesn't mind fighting people in public. I have seen him on occasion shaming fellow senior scholars for bad scholarship, though not necessarily for plagiarism. I do not have any personal ties to this reviewer and I am not sure how catastrophic the situation will become (at least, for me as a job seeker) once he decides to pursue the case.