GREENWICH, Conn. (Reuters) - One of the most stubborn unsolved murders in modern American history, the Martha Moxley case has inspired nonfiction books, a best-selling novel, a Web site and countless news stories.

One thing the Connecticut teenager's brutal 1975 slaying has not produced so far is a conviction -- or even an arrest. Now this could change as a state grand jury enters the final stretch of a maximum 18 months it has to investigate the case.

Bridgeport Superior Court Judge George Thim began his work as a special one-man grand jury in June of 1998. Grand juries, rare in Connecticut, have the power to subpoena witnesses and ultimately to recommend an indictment.

Moxley, 15, was savagely beaten to death with a golf club on the night of Oct. 30, 1975. A friend found her body the next day under a pine tree on her parents' lawn in Belle Haven, the wealthiest enclave in Connecticut's richest city, Greenwich.

``She was bright, funny, outgoing, and very popular,'' said Tom Alessi, a former classmate who runs the Web site at www.marthamoxley.com devoted to news and clues on the case. The site has had 61,000 ``hits'' from around the world since its creation last September, Alessi told Reuters.

``I know nothing will bring Martha back and the only people I'm really upset with is the person who killed Martha and those who helped cover it up,'' her mother, Dorthy Moxley, said in a telephone interview from her home in Chatham, New Jersey.

BACKDROP OF EXTREME AFFLUENCE

What makes the case different from other unsolved murders is its backdrop of extreme affluence and a cast of characters touching the deepest chords of American power and celebrity.

Among the last two people who saw Moxley alive on that chilly autumn night were her neighbors, Thomas Skakel, then 17, and his brother, Michael, 15. They are the sons of Rushton Skakel, the wealthy industrialist brother of Ethel Skakel Kennedy, Robert F. Kennedy's widow.

Police soon found that the murder weapon, a six-iron golf club, came from a set owned by the Skakel family. ``The murder weapon itself is almost comically suited to Greenwich -- the first object that would come to the hand of an angry rich person,'' Tim Dumas wrote in his 1998 book, ``Greentown: Murder and Mystery in Greenwich, America's Wealthiest Community.''

The book by Dumas, a Greenwich native who was a year behind Moxley at the same school, was one of two nonfiction works on the case last year. The other was ``Murder in Greenwich'' by Mark Fuhrman, the former Los Angeles police detective who gained notoriety during the O.J. Simpson criminal trial.

In addition, Dominick Dunne helped get the stalled Moxley case back on the map with his best-selling 1993 novel that was loosely based on the killing, ``A Season in Purgatory.''

In the first days after the murder, police learned that the Skakel boys had a reputation for hard drinking and volatile behavior -- particularly Michael, who liked to corner chipmunks and squirrels and bash them to death with a golf club.

The Skakels have strongly and repeatedly denied any involvement in the murder from the very beginning.

INITIAL POLICE WORK FLAWED

Murders were rare in Greenwich and initial police work on the case was flawed. ``You had an inexperienced police force going up against people with a lot of sophistication, money, and top-notch lawyers,'' Dumas told Reuters.

For various reasons, the investigation fizzled and then fell dormant in the early 1980s. It might have stayed that way but for a freak occurrence: the 1991 rape trial of William Kennedy Smith, nephew of John and Robert Kennedy.

The trial sparked a rumor that Smith was at the Skakel house on the night of Martha's slaying. The rumor proved false, but it generated a buzz and led to some new leads in the case. Then, in the next few years, the books started appearing.

It was amid this renewed interest in the case that the grand jury began its work.

``I have been hoping and praying for a grand-jury investigation for years -- it's wonderful,'' said Dorthy Moxley, whose husband died at age 57 in 1988.

Grand juries operate in secrecy and there is no way of knowing exactly what Judge Thim is up to. Prosecutors are not talking about the case either. But Michael Skakel's lawyer, Mickey Sherman, said it was reasonable to assume his client was the main focus of the probe based on the identities of the 50 witnesses who have been called to testify.

``It seems to me obvious that Michael is the main focus of this grand jury based on the fact that they're spending so much time, effort, expense and energy on learning things that were allegedly said at the Elan program,'' Sherman said.

Skakel attended the Elan School in Poland Springs, Maine, an alcohol and drug rehabilitation center, between 1978 and 1980. What he may or may not have said about the Moxley slaying to Elan enrollees is a subject of intense debate.

'NOTHING HAD CHANGED' IN SKAKEL DENIAL

``Michael Skakel has consistently denied any involvement whatsoever in this tragedy,'' Sherman said. ``Nothing has changed that. No amount of spin by Mark Fuhrman or anyone else can change that, it's as simple as that.''

For many years, Tommy Skakel was considered a prime suspect because he was the last person known to have seen Moxley alive, police and investigators have said. The other main suspect was Ken Littleton, then 23, a tutor and live-in baby-sitter at the Skakel house in 1975. He was eventually ruled out and the grand jury granted him immunity last year in exchange for testimony.

Sherman agrees with other close observers of the case that, with Littleton absolved, the Skakels are the suspects. ``They're not sharing the fruits of the investigation but you don't have to be a rocket scientist to figure that out,'' he said.

After years of alcohol abuse, Michael Skakel has cleaned up his life and lives in Hobe Sound, Florida, with his wife and young child. He is ``very upset'' about the grand jury probe, Sherman said.

``He's very much looking forward to a swift end to this investigation,'' Sherman said. ``He knows he will be exonerated, and he'd like that to happen.''

Moxley declines to say who she thinks killed her daughter but says, ``I do believe that whoever killed Martha was at the Skakel house that night, and it does look like one person is the most logical.''

Copyright 1999 Reuters News Service. All rights reserved.