The word souvenir does the case no favours. It suggests a memento of an experience that ended, and in most of these cases the point of the object was that the experience had not ended.
Ed Gein is the extreme, and also the most misread. What was found in the farmhouse outside Plainfield in November 1957 was not a collection of keepsakes taken from murders. It was material, most of it lifted from graves: masks made from women's faces, bowls made from skullcaps, a lampshade, chair seats, a belt of nipples, a shoebox of preserved genitals, skulls on the bedposts, and a wearable suit of skin. Objects were traced to at least ten women. He confessed to two murders and to robbing nine graves, and he said he had been trying to understand the female body and that he wanted to become a woman himself. He was found not guilty by reason of insanity. Almost everything the public believes about him arrived by way of Psycho, The Texas Chain Saw Massacre and The Silence of the Lambs, and the films took the furniture without the explanation.
Edmund Kemper kept heads. He killed six women he picked up hitchhiking around Santa Cruz between May 1972 and February 1973, took the bodies to his mother's house or to motels, decapitated them, had sex with the remains, and disposed of the rest in the hills. He had killed his grandparents at fifteen, in 1964, and told police he had wanted to see what it felt like to kill his grandmother. He was found sane and guilty on eight counts of first degree murder in 1973, has waived or been denied parole repeatedly, and has said himself that he should never be released.
Jeffrey Dahmer's keeping was structural rather than sentimental. In Apartment 213 he photographed the bodies in stages, dismembered them in the bathroom, and kept skulls, hands and genitals. When police went in on July 22, 1991, after Tracy Edwards got out with a handcuff still on his wrist, they found the Polaroids first, then three severed heads in the refrigerator and freezer, skulls in a filing cabinet, a barrel of acid and remains through the flat. In his last months he had begun drilling into the skulls of living men and injecting acid, trying to produce someone who would stay. That is the clearest statement any of these cases makes about what the keeping was for.
Arthur Shawcross was caught by what he went back to. On January 3, 1990 a State Police helicopter crew over Salmon Creek saw a man standing on a bridge above a body that had not been recovered yet, masturbating over it. They took his registration and traced the car. He confessed across eleven days of interviews. He had already served fourteen and a half years of a twenty-five year sentence for a 1972 manslaughter and been paroled in April 1987. He was convicted of ten murders in December 1990 and pleaded guilty to an eleventh.
Ted Bundy sits slightly outside this group, and the difference is instructive. What convicted him in Miami in 1979 was a bite mark on Lisa Levy's body matched to his teeth, and an eyewitness. There was no cache. The count of around thirty rests on what he said in his final days, and nothing physical was ever needed to make him talk.
Reading the five together, the objects divide fairly cleanly. Gein made things out of bodies, most of which he did not kill. Kemper kept the part of the person he had been looking at. Dahmer kept what he had photographed. Shawcross kept the site rather than the object and had to keep returning to it, which is exactly what put him under a helicopter. None of it is trophy-taking in the sporting sense the word implies. It is an attempt to stop something from being over.