Kennedy cousin Michael Skakel was sentenced to 20 years to life in prison for the 1975 murder of 15-year-old Martha Moxley.
Skakel, the 41-year-old nephew of Robert F. Kennedy's widow, Ethel, was convicted of murder on June 7.
He wept as he testified today, maintaining his innocence.
He faced a minimum of 10 years to life in prison and a maximum of 25 years to life for the bludgeoning death of his teenage neighbor, Martha Moxley, in 1975.
Norwalk Superior Court Judge John Kavanewsky Jr. today rejected the defense team's assertion that the prosecution withheld key evidence during the trial.
Skakel's lawyers argued prosecutors improperly withheld a police sketch that suggested someone else could have killed Moxley. The sketch, defense attorneys said in their motion, resembled former suspect in the case, Kenneth Littleton, the Skakels' live-in tutor.
"One of the defenses pursued at trial involved a claim that Kenneth Littleton may have been the killer," the defense motion says. "Disclosure of the composite drawing would have been the linchpin for such a defense, and in all likelihood would have resulted in a verdict of not guilty."
The defense motion also accused prosecutors of not disclosing reports by a state investigator detailing evidence against Littleton and Skakel's older brother, Thomas.
Prosecutors insisted the sketch and other evidence was available to the defense and would not have altered the outcome of the trial.
After rejecting the motion for a new trial, Kavanewsky continued today to review submissions from Skakel's family, who were asking for a lenient sentence. Skakel's lawyers filed more than 100 pages of documentation Tuesday, including a letter from Robert F. Kennedy Jr., claiming that Skakel was a sensitive child who had been abused by his alcoholic father.
Skakel has maintained his innocence, and his lawyers are appealing his conviction.
Old Sentencing Rules May Help Skakel
Skakel's incarceration could potentially be cut in half because Connecticut sentencing rules that were in effect at the time of Moxley's slaying allow time off for good behavior. Those same sentencing rules also make Skakel eligible for parole.
Both these guidelines have since been abolished in Connecticut.
Moxley's body was found in the early hours of Oct. 31, 1975, on her family's estate in an affluent neighborhood in Greenwich, Conn. Police said the 15-year-old was beaten to death with a golf club from the Skakel home, which was next door to the Moxley house.
Prosecutors convinced jurors in June that Skakel, who was also 15 at the time of the murder, had been competing with his older brother, Thomas, for Moxley's affections and that Michael clubbed the girl to death when she rejected his sexual advances.
Skakel's conviction surprised many courtroom observers because prosecutors did not have any physical evidence linking him to the killing and there were no eyewitnesses.
Because of the time that had passed since the slaying and the lack of physical evidence, prosecutors had to rely largely on circumstantial evidence. Over the course of 27 years, some evidence was not preserved, potential witnesses died and the memories of living witnesses were open for challenge.
Prosecutors: Skakel Convicted by His Mouth