WHEN MURDER BECAME MYSTERY TRACKED IN HISTORIAN'S NEW BOOK In the late 20th century, a murder with no mystery about it is hard to imagine. Yet, murder as mystery is a relatively new phenomenon, says a UC Davis historian. In her recent book "Murder Most Foul: The Killer and the American Gothic Imagination" (Harvard University Press), professor Karen Halttunen traces the linkage of murder and mystery as she examines the cultural evolution of American attitudes toward murder from the late 17th century through the 1800s. What she finds is that as recently as the 18th century, little doubt was expressed about who had committed a murder. "In a world where God sees all and knows all, there was less mystery to murder. But after the Enlightenment, as God seemed to recede from the universe, humans were left with the problem of uncovering all. Judicial knowledge is faultier than theological certainty," she says. "It becomes hard always to know who committed a crime." Among the surprises in her research, Halttunen says, is her finding that the "fascination with violent deaths that we tend to think of as a contemporary phenomenon goes back to the late 18th century, but doesn't really appear before then. Earlier, people didn't dwell on the crime, the violence, the corpse." Halttunen, who worked on her book for 12 years, says she arrived at the topic of murder when she pondered the question "What happened to American understanding of human evil after the Enlightenment? How on earth did people come to describe truly evil transgressions? I decided that attitudes toward murder would be an excellent window on the matter."