By Chris Francescani

NEW YORK (Reuters) - A New York City police officer accused of plotting to kidnap and cannibalize women had been having dark fantasies since he was a teenager, but had no intention of ever turning those thoughts into reality, his attorney said on Monday at the start of his federal trial.

Attorney Julia Gatto also said that Officer Gilberto Valle, who faces 20 years to life in prison if convicted, talked online about torturing his own wife and her female friends and colleagues.

"What really turns on is the idea of a woman - oiled, bound, laid out on a platter with an apple in her mouth, about to be cooked," Gatto told jurors in opening arguments. "That's his dirty little secret."

She argued that Valle was engaged in online sexual fantasy role play involving a little-known internet subculture where people with unconventional desires gather to act them out in cyberspace but with no intention of every carrying out criminal acts.

"There are literally thousands and thousands of people doing the same thing, online, every day," she told jurors, saying that government investigators misunderstood what they found on his computer.

Federal prosecutors countered that Valle, who has pleaded not guilty, took the plot beyond fantasy and into real life when he "engaged in surveillance of some of the women he was targeting."

Prosecutors say Valle 28, improperly accessed a federal law enforcement database to get information about one woman, and met a second women - a former classmate - for brunch.

Assistant U.S. Attorney Randall Jackson also said Valle searched online for homemade recipes for chloroform to subdue victims and recipes for cooking human flesh.

"Make no mistake," Jackson told jurors. "Officer Valle was deadly serious."

Valle's estranged wife testified Monday that she placed web tracking software on the couple's computer last fall after she said he began acting strange. When asked what she discovered, she burst into tears. Continued...