UPDATE 1-Closing arguments begin in New York 'cannibal cop' case

(Adds prosecutor's statement)

By Chris Francescani

NEW YORK, March 7 (Reuters) - New York City's accused "cannibal cop" crossed the line from fantasy to reality in plotting to kidnap, cook and eat women, a federal prosecutor told a jury on Thursday in closing arguments.

Police Officer Gilberto Valle, 28, has pleaded not guilty to a charge of conspiring to kidnap, saying he had merely engaged in online fetish role play. His defense attorney would get a chance to address jury later on Thursday.

Valle is charged with improperly accessing a law enforcement database to gather personal information about purported targets, which carries a maximum sentence of five years in prison if he is convicted, and conspiracy to kidnap, which carries a sentence of 20 years to life.

Assistant U.S. Attorney Hadassa Waxman acknowledged Valle was engaged in fantasy but that his intentions had grown more sinister.

"Officer Valle crossed the line. He left the world of fantasy and entered the world of reality," Waxman said in her 50-minute statement summarizing the prosecution evidence.

"He was serious. He was not just entertaining himself. He would have carried out the plan if he thought he could get away with it," Waxman said.

She pointed to his extensive online research on how to commit kidnapping, how to make chloroform, and how to cook women.

"None of this is fake. None of this is imagined. These are real searches conducted to carry out real research to kidnap real women," she said.

Valle, dubbed the "cannibal cop" by tabloid media, did not testify. Defense attorneys scrapped a plan to call a psychiatrist to testify that he suffered from a disorder in which he derives sexual pleasure from others' suffering.

The trial has brought to light a shadowy region of cyberspace where millions of people discuss and exchange images and video of extraordinary brutality, much of it staged.

On Tuesday, defense attorneys took jurors on a video tour of DarkFetishNet.com, a website at the heart of Valle's case.

The website functions like mainstream social media networks and its creator, Russian web entrepreneur Sergay Merenkov, likened it to Facebook. However, instead of family photos and cat videos, members share photos and videos of extreme human cruelty - including rape, asphyxiation and beheading - with the goal of sexual stimulation.

Members dream up brutally violent scripts, said Merenkov, who has kicked members off the site when "let's say that it seemed not to be fantasy anymore."

Prosecutors said Valle revealed himself to be such a person when he began taking steps to act on his fantasies. (Reporting by Chris Francescani; Editing by Daniel Trotta, Alden Bentley and Bernadette Baum)