Kennedy kin Skakel murder sentence affirmed Mon Mar 5, 2012 6:32pm EST (Reuters) - Kennedy relative Michael Skakel was denied a reduction in his sentence of 20 years to life in prison for the 1975 murder of his 15-year-old neighbor, according to court documents released on Monday. Skakel, 51, nephew of Ethel Kennedy, asked a three-judge panel in Connecticut Superior Court to reduce his sentence, initially imposed a decade ago, saying he should have been sentenced as a juvenile not an adult. The panel affirmed the sentence, noting "nothing inappropriate or disproportionate about the sentence imposed by the trial court in this case," the decision said. His attorney had argued the trial court overemphasized Skakel's lack of remorse, saying Skakel had addressed the panel and said he did not commit the crime, court documents showed. Skakel was 15 years old at the time of the 1975 murder of Martha Moxley, a 15-year-old neighbor in Greenwich, Connecticut who was beaten to death with a golf club. Her body was found on the lawn of her parents' home in the affluent New York City suburb. Prosecutors said the murder was vicious and violent and that the sentence was appropriate. The victim's brother, John Moxley, addressed the judicial panel and requested the sentence be affirmed, according to court documents. The U.S. Supreme Court in 2006 declined to hear an appeal by Skakel seeking to overturn his conviction on grounds that his constitutional rights had been violated because Connecticut's five-year statute of limitations, in place at the time Moxley died, had expired when he was charged in 2000. In 2009, lawyers for Skakel sought a new trial to overturn the conviction saying new evidence implicated other men. Reporting By Lauren Keiper; Editing by Paul Thomasch