GANGING UP ON MOVIE'S 'LIES'

Hit film "American Gangster" whitewashes the seedy story of a ruthless Harlem drug dealer, says the former prosecutor who inspired one of the film's central characters and who cooperated with the filmmakers.

The movie is now stuffing the pockets of the former druglord, who is legally able to profit from his crimes.

Frank Lucas, a Harlem heroin kingpin of the 1960s and '70s portrayed by Denzel Washington, was convicted in 1975 of conspiracy to distribute heroin. Because the conviction occurred before the passage of the "Son of Sam" law, Lucas is not banned from selling the story of his crimes.

Lucas has already received $300,000 from Universal Pictures and another $500,000 from the studio and Washington to buy a house and a new car, a source in the production told The Post.

Lucas says he also has plans for a gangster video game and a clothing line, and is negotiating a possible sequel to the film.

"Gangster" - which was expected to top the box office this weekend after beating all competitors with a $15.8 million opening Friday - tracks the rise and fall of Lucas along with the story of his dogged law-enforcement nemesis, Richie Roberts, played by Russell Crowe.

In the movie, Lucas is shown ruling an international heroin empire with an iron fist but having a serious soft side. Roberts is shown as a straight arrow at work, but cheats on his wife and loses custody of his child.

"The parts in the movie that depict Frank as a family man are ludicrous," Roberts told The Post. "They did it for dramatic purposes, you know, to make him look good and me look bad."

Roberts says the portrayal of his relationship with his first wife is offensive - for one, they didn't have a child together, although the film shows them in a custody battle.

But Roberts' main beef is with the studio's depiction of Lucas as almost noble. Among the exaggerations or plain factual errors, he says, are Lucas being moral with his family, modest in dress and behavior, and a straight dealer in business.

Roberts called one scene, in which Lucas holds his family members' hands in prayer at a Thanksgiving feast, "sickening." Sources have said Lucas manipulated his family, bringing them from North Carolina to work for his drug business, and even put out a contract on his own brother.

Cops and prosecutors who worked the case say the film inflates Lucas' role in Harlem's drug scene, and contains dozens of falsehoods, like the prevalence of dirty cops and the transport of heroin in the caskets of Vietnam soldiers.

"The whole film is a bunch of lies," said Dominick Amorosa, the lead prosecutor in the 1975 federal case in which Lucas was sentenced to 40 years in prison (he served only seven). Roberts prosecuted a New Jersey case against Lucas.

"They claim it's based on a true story," said New York-based Drug Enforcement Administration agent Joseph Sullivan, who was at a raid on Lucas' Teaneck, N.J., home after two members of the Mafia ratted Lucas out.

"His name is Frank Lucas and he was a drug dealer - that's where the truth in this movie ends."

Even Lucas admitted to sources that "only 20 percent of the film is true."

Roberts conceded that his role in the film is also misleading: "It took more than just me to bring down Frank Lucas."

A Universal spokesman said it is "completely expected that there might be conflicting versions of these incidents, as there are whenever narrative choices are made to dramatize a film based on real people and events," adding, "the material facts are conveyed truthfully."

scahalan@nypost.com