Lawyers for Michael C. Skakel, who was convicted in June 2002 of the 1975 murder of Martha Moxley, filed an appeal here on Monday in State Supreme Court.  The appeal challenges the conviction on seven grounds ranging from whether the state inflamed the jury by referring to him as a ''spoiled brat'' during the trial to whether Mr. Skakel should have been tried as an adult since he was 15 when Ms. Moxley was slain. Mr. Skakel, 43, is serving a sentence of 20 years to life. If he had been convicted as a juvenile, he would have faced little or no prison time.  The trial of Mr. Skakel, a nephew of Ethel Kennedy's, attracted intense media scrutiny due in part to the Kennedy name and the aura of mystery that clung to the murder. The body of Ms. Moxley, a pretty, vibrant 15-year-old, was found under a pine tree in a gated community in Greenwich. She had been bludgeoned to death with a golf club belonging to the Skakel family.  The 75-page appeal says Mr. Skakel should not have been tried at all because the statute of limitations in 1975 was five years. The appeal also says prosecutors engaged in a pattern of misconduct during closing arguments, including inflaming the jury by creating what the defense described as a ''fictional confession'' by Mr. Skakel during an audio-visual presentation at its closing arguments that showed graphic images of Ms. Moxley's battered body. Mr. Skakel's words, culled from a taped conversation in 1997 between him and the ghostwriter of his autobiography, were edited to imply an admission of guilt, the defense said.  The appeal says the state wrongly suppressed the introduction of a sketch, which it describes as ''the single most important'' piece of evidence exonerating Mr. Skakel: a composite police drawing of a man observed by a neighborhood security guard on the road near the scene and time of the murder. The appeal says the man resembled Kenneth W. Littleton, the Skakel family tutor at the time of the murder and once a prime suspect in the murder. The sketch was not disclosed by the state until after Mr. Skakel was convicted. The appeal also says evidence that incriminates Thomas Skakel, Mr. Skakel's brother, should have been admitted.  Jonathan C. Benedict, the chief prosecutor in the trial, who had not yet seen the appeal, said, ''I'm not aware there is anything in it that was not previously addressed at the trial level.''  The appeal is expected to be followed by a motion for a new trial that argues -- based on newly discovered evidence -- that Mr. Skakel was wrongfully convicted. A new witness claims that two young men visiting Greenwich from the Bronx picked up a golf club from the Skakel property and boasted about attacking a girl ''caveman style.'' The grip of the golf club used in the killing has never been found.  Christopher Morano, one of the prosecutors in Mr. Skakel's trial who is now chief states attorney, said that ''despite repeated requests'' to the defense team, his office had received no information about other possible suspects. Hope C. Seeley, one of Mr. Skakel's lawyers, said none would be released until the motion was filed.
Michael C Skakel files appeal of his 2002 conviction for murder of Martha Moxley in Greenwich, Conn, on seven grounds (M)