Looked like a clear invalid fair catch signal to me. It was invalid but still has the effect of the valid one in that ball should be dead when possessed. Maybe we will hear from Big East this week as there will be considerable media play on this. Replay rules do not specifically cover fair catches but 1 category of reviewable plays seems applicable: "A runner judged not to be down by rule"
The video:
http://www.youtube.com/v/rbRdZZ1kfag