It was one of the most bizarre and bumbling kidnappings of the 1960s: Three young men of promise abduct Frank Sinatra Jr. from a motel at gunpoint, demand and get $240,000 ransom from his legendary father, then blow the whole scheme by getting caught just days after they let him go.

Sound like a movie? It will be soon, and Barry Keenan, who was the ringleader of the kidnapping and spent four years in prison for his crime, stands to collect a handsome profit from a deal he struck in Hollywood for the rights to make a film about the caper. But the California Supreme Court may not let him have a cent.

And therein lies another story, an unresolved tale about the competing rights of convicted criminals and their victims and whether, in essence, crime should ever pay.

At issue is a California statute that forbids felons from profiting financially when the stories of their wrongdoing are told or sold. It's popularly known as a "Son of Sam" law, a reference to New York serial killer David Berkowitz and his groundbreaking attempt in the late 1970s to explain his crimes for money. Most states have similar measures on the books, but the new challenge to California's statute is emerging as the most important national test in nearly a decade of whether such a law violates free speech.

Keenan, now a successful real estate developer in his late fifties, insists that it does. In court papers, he contends that he has paid his debt to society and has a constitutional right to sell his story.

"This is an important First Amendment case," said Stephen Rohde, his lawyer. "You cannot marginalize his speech just because he was a criminal many years ago."

But the junior Sinatra has been working zealously through the courts to prevent Keenan from getting paid for the upcoming film. Sinatra's legal advisers liken the money he could receive to a "second ransom." Neither man is publicly discussing the case.

"This does not limit free speech," said Richard Specter, Sinatra's lawyer. "This only impacts paid speech. If this law is struck down, victims across the country will lose, and criminals will win."

The debate is in many ways a sign of the times: Movie companies and publishing houses have the receipts to prove how popular true crime stories are with audiences. The genre has become embedded in the culture. Even the teenagers responsible for the massacre at Columbine High School in Littleton, Colo., this year bragged on just-released tapes that "directors will be fighting over this story." But as that entertainment market grows, so too is the influence that victims' rights groups have in state legislatures.

Until recently, the slapstick saga of the junior Sinatra's brief kidnapping in December 1963, a national sensation at the time, had been largely forgotten. But two years ago writer Peter Gilstrap interviewed Keenan and published his strange story of the crime, which took place in the resort town of Lake Tahoe, Nev., and unraveled soon afterward all over Los Angeles, in New Times, a local weekly here.

In that account, Keenan details how as a down-on-his-luck young businessman, broke and dazed by an addiction to painkillers for a bad back, he concocted an elaborate plot to squeeze cash from Frank Sinatra by capturing his son. It was not a random choice. Keenan had been a friend of Sinatra's daughter, Nancy, when they attended high school together in Los Angeles and told Gilstrap that at the time he figured it would not be "morally wrong" to give the singer some grief because he "always got his way."

Keenan was a novice criminal, but a clever one. He and a friend managed to snatch 19-year-old Frank Jr. from a motel, hide him in Los Angeles for a few days, and collect the ransom Sinatra left at a drop point on Sunset Boulevard. Nothing went as planned but somehow it all worked--until the brother of one of his cohorts turned them in. Keenan received a life sentence. It eventually was reduced to less than five years.

As soon as Gilstrap's interview with Keenan hit print, it ignited a high-stakes Hollywood bidding war to bring the tale to the big screen. Eventually, Columbia Pictures won the right to "Snatching Sinatra" by offering Keenan and others a total of $1.5 million in return for their cooperation in recounting their story. But Frank Sinatra Jr., who is now a bandleader and singer, swiftly filed suit and won a court order that prevents Columbia from paying his former kidnapper.

The legal battle was on. Keenan has challenged that ruling and California's Son of Sam law in state courts for the past year, to no avail. Now, backed by the Southern California chapter of the American Civil Liberties Union, he has gone to California's Supreme Court, and it has decided to review the case.

Some constitutional scholars say resolving the case will not be easy because of its complex First Amendment implications. "This is a close and difficult case," said Stephen Barnett, a law professor at the University of California at Berkeley. "A lot of these laws have not been tested, so it could be a very important one, too."

The U.S. Supreme Court has ruled on the issue once. In 1991, in a case involving a mobster's memoir, it struck down the nation's first Son of Sam law in New York on the grounds that it was so broad it could suppress free speech. A publishing house was allowed to pay the mob figure profits from his book.

The New York law covered anyone accused of a crime, not just convicts, and it subjected even passing references to the crime in someone's book or film to its requirements. But since the high court's decision, most states have narrowed the scope of their Son of Sam laws. California revamped its own a few years ago, applying it only to convicted felons and works that focus on, not just mention, a particular crime.

Allies of Keenan contend that the law is still unconstitutional. They say that by its standards, money earned even from landmark works of literature such as Henry David Thoreau's "Civil Disobedience" or "The Autobiography of Malcolm X" possibly could have been kept from their authors. They contend that crime victims or their families have other routes through the courts to seize or limit the assets of criminals. They also argue that Keenan should not be subject to the law because it was created so long after his crime.

"This law could do grave damage to the fundamental rights we all cherish," said Dilan Esper, an attorney for the American Civil Liberties Union.

But so far courts in California have said the law does not pose any of the problems that the one in New York had. Some legal analysts also say that in its rejection of New York's law, the Supreme Court made a point of noting that it was not questioning the constitutionality of every statute with a similar purpose.

In court papers, Sinatra's camp contends that while Keenan and others have an absolute right to speech, no matter how offensive it may be, the government has a compelling interest to stop criminals from reaping rewards from their unlawful actions.

"You shouldn't be able to put a gun to someone's ear and kidnap them," Specter said, "then cash in."

Some families of crime victims are so fearful that Keenan's fight will lead to the demise of the California law that they are taking other steps to prevent criminals from profiting on their stories.

Relatives of three women who were slain at Yosemite National Park this past summer already have sued Cary Stayner, the man police say has confessed to the killings, to collect any money he could receive from selling his story--something he apparently is trying to do from jail as he awaits trial.

Ironically, Stayner's family already has been the subject of a television mini-series based on the grim ordeal his younger brother suffered years ago when he was kidnapped, held captive and sexually abused.

"He knows how this works," said Zachary Zwerdling, a lawyer for the family of two of the slain women, Carole and Juli Sund. "Americans seem to love watching these things get dramatized, and there's definitely big money to be made from it. We want to put a stop to it."

CAPTION: Agents take Barry Keenan into custody in 1963 in the kidnapping of Frank Sinatra Jr. Three decades later, Keenan, above, is at center of a dispute over whether crime may pay.