NY cannibal cop trial to spotlight violent sex fantasy subculture NEW YORK (Reuters) - The New York federal trial of accused "cannibal cop" Gilberto Valle due to start on Monday promises to highlight an online subculture where people trade violent sexual fantasies. Sex crimes prosecutors, First Amendment defense attorneys and sexual behaviorists said they had never before heard of a suspected conspiracy to commit a violent sexual crime begun on a website for violent sexual fantasy role play. "It's the perfect alibi," said former Manhattan sex crimes prosecutor Linda Fairstein, who is not involved in the Valle case, which is being prosecuted in Manhattan by the U.S. Attorney's Office for the Southern District of New York. "A case of this magnitude, and of this nature, may make case law," Fairstein said. Opening arguments were expected to begin Monday afternoon. Valle has pleaded not guilty to conspiring with New Jersey mechanic Michael Van Hise to kidnap, cannibalize and kill a Manhattan woman. Valle has said he was merely engaged in online fetish role play and never intended to commit a crime. Federal authorities contend he took real action outside the role play websites. Investigators say Valle compiled an online dossier with the names and in some cases photos or physical descriptions of more than 100 women, and discussed targeting some of them for kidnap and murder. They say he met one woman for brunch, improperly accessed a police database to get information on another, and engaged in surveillance of a third, a high school senior of whom Valle wrote to a fellow fetishist that "she is the most desirable piece of meat I've ever met." Prosecutors have also said Valle searched online for homemade chloroform recipes so he could "knock out" a Manhattan woman and deliver her to Van Hise. The pair also discussed "slow cooking" the woman to keep her alive as long as possible, prosecutors contend. Defense attorneys for both men have said the goal of role-play is to make it as realistic as possible, enhancing the thrill. "You draw on your real life to make it as real as possible, but it's fantasy," Van Hise's attorney Alice Fontier told a judge recently. Sex crime investigators have been monitoring chat rooms and fetish websites for child molesters since the advent of the internet. But violent sex fantasy role playing sites present a new level of legal complexity. "Everybody is concerned about individuals whose sex fantasies reflect a dangerous mindset," said Martin Klein, a sex therapist who has testified in state and federal sex crimes cases. The problem is the people that are actually dangerous - their fantasies tend to look very, very similar to those of healthy people. On the Internet, the line between imagination and behavior has gotten really very thin. Additional reporting by Elizabeth Dilts; Editing by Daniel Trotta and Eric Walsh