Original: In the backstory , FBI special agent Will Graham , who investigated Lecter 's murders but was unaware of his involvement , initially consulted Lecter about the case before realizing he was the culprit ; Lecter nearly killed Graham when he was captured . The plot finds Graham consulting Lecter in order to catch another serial killer , Francis Dolarhyde , known by the nickname '' The Tooth Fairy '' .
Simplified: Will Graham , the agent who caught Lecter , is at first very offended by Lecter 's demeanor , but comes to appreciate his help when Lecter gives him insight into the way Dolarhyde 's mind works .