William Monahan (The Departed) will write a fact-based thriller for Paramount based on an article that will appear in Playboy later this year.

According to Variety, it's the story of a drug dealer who traded a prison sentence to go undercover at a maximum security hospital for the criminally insane, where he tried to get a serial killer to divulge the whereabouts of his victims.

The son of a police chief, Keene fell from grace after he was caught dealing drugs. As an alternative to a 10 years-to-life sentence, he was allowed to cozy up to a man authorities believed murdered 25 young women. Only the prison psychiatrist knew Keene was undercover, plus a visiting "girlfriend" who was actually an FBI agent.

No production date has been set.