2 come to mind. The first, the aforementioned James Klindt. You could see Jim's castle house from the backyard of the house where I grew up in Davenport. Jim's wife, Joyce, was good friends with our next door neighbor. The next door neighbor was her hair dresser and had to testify at trial as to the color of Joyce's pubic hair (i.e. natural hair color) since authorities only found Joyce's torso. Jim and Joyce (and their son, Bart) often came to our block parties. Jim was always a bit off.
The second was Loren Huss. When I was in law school at the Univ. of Iowa, I worked one summer in the legal clinic. Loren was our client, and I had to go to Anamosa's penitentiary to meet with him. Loren was convicted of 1st degree murder of his live-in girlfriend during a psychotic episode and we were trying to get the sentenced reduced. According to Loren, the murder occurred when his girlfriend approached him wearing a white robe and told him to come to bed. At first, Loren thought his girlfriend was Jesus Christ, but then thought it was Satan in disguise because Jesus Christ would never ask another man to come to bed with him. Because of that, Loren felt the need to kill who he thought was Satan.