Dr. Keller
Background
Paul Keller is a doctor of parapsychology in Florida. He can communicate with the spirit world. Dr. Keller used to work with prisoners.
During the events of Ruby (1977) played by Roger Davis
Dr. Keller stops by the theater and Vince Kemper asks him if it is true that he can communicate with spirits. Vince tells him that a spirit is trying to kill the old gang. Dr. Keller walks around the movie theater and swamp and can sense that there has been a murder in the past. Vince introduces Dr. Keller to Ruby Claire and Leslie Claire comes into the room and rubs Dr. Keller's hand against her face and then bites his hand. Dr. Keller senses something in the room that is angry.
Ruby does a performance for Dr. Keller and as she is staring at Leslie, Leslie's face changes to Nicky's. Dr. Keller starts asking questions and Ruby gets upset and goes to her room. The next morning Dr. Keller asks Vince about Leslie and thinks she is the key to what is happening. He thinks Leslie is fighting back, because she knows Ruby wanted to send her away. He tells Ruby and Vince that he wants to try and hypnotize Leslie. He hypnotizes her and Leslie starts to speak. He asks her to think about things in her past and Ruby's face suddenly has bullet holes in it and then they disappear.
Ruby tells Dr. Keller how Jake had her seduce men who would later be killed by Jake and the other members of the gang. The body of Jake rolls into the room with a knife stuck in his chest. Dr. Keller senses a spirit is among them and he and Ruby run up to Leslie's room. Dr. Keller calls Vince and tells him to get away from the theater. Leslie attacks Dr. Keller and Dr. Keller runs to Vince and tells him that the ghost of Nicky is in the house. They hear Leslie screaming and find her back to her normal self. Dr. Keller tells Vince that Ruby is gone. Ruby is walking near the swamp when she sees Nicky and walks with him towards the swamp. Vince tries to stop her, but Dr. Keller tells him it is what Ruby wants. Ruby is then pulled into the water by Nicky who drowns her.