The Mephisto Club
One of the Antagonists in the story is Joyce O'Donnell. She is a psychiatrist that basically only deals with murderers and others with twisted views of reality. In this case one murderer seems to be trying to directly contact Joyce as he is done killing. This motivates Joyce to be uncooperative with the investigations because she believes in confidentiality with her clients even though they are murderers. She will do anything to hear the details of a murder and why the person did the horrible things they did. She does not care how she gets the story, just as long as she gets it and she doesn't get hurt. Even if she hears many disturbing stories and the reasons why they were committed, she will not be satisfied. She is always looking for the next best thing.