NORWALK, Conn. (AP) — Michael Skakel's lawyers argued at his sentencing hearing Wednesday that his murder defense was hamstrung by the prosecution's failure to turn over a police sketch that could point to an earlier suspect.

The defense claims the sketch, a drawing of a man spotted by a police officer the night of the October 1975 murder, resembles Skakel family tutor Kenneth Littleton.

Littleton, who had started his job the day Martha Moxley was killed, was an early suspect in the investigation, and Skakel's lawyers repeatedly suggested during the Kennedy cousin's trial that Littleton was the killer.

Defense attorney Hubert Santos said the sketch would have been critical at the trial if prosecutors had turned it over.

"At minimum, there would have been a hung jury," Santos said in a defense presentation that lasted until late morning.

Prosecutors have said previously the man in the sketch was identified as a neighbor who was cleared of involvement in the murder, and that Skakel's attorneys were given police reports that mention the sketch.

Skakel, 41, a nephew of Ethel Kennedy, was convicted in June of beating Moxley to death when they were 15-year-old neighbors in Greenwich. Under the guidelines in effect in 1975, Skakel could receive a minimum sentence of 10 years to life in prison and a maximum of 25 years to life.

Skakel's defense continues to maintain he is innocent.

Skakel's lead trial attorney, Michael Sherman, also argued Wednesday prosecutors used "subliminal messages" in their closing arguments by showing photos of Martha's autopsy while they played a tape of Skakel discussing his movements the night of the murder.

"I think it would be terrific if you're selling cars," Sherman said. "That can only have an absolutely devastating effect on the jury."

Sherman also said Superior Judge John F. Kavanewsky Jr. erred when he allowed prosecutors to use testimony by a former classmate of Skakel.

Gregory Coleman, who attended a substance abuse treatment center with Skakel in the 1970s, testified in a pretrial hearing that Skakel once told him: "I'm going to get away with murder, because I'm a Kennedy."

Coleman died last year after using drugs, but his comments were read into the record of the trial. Coleman had admitted in the pretrial hearing that he was high on heroin when he told a one-judge grand jury about Skakel's remark, but stood by his testimony.

On Tuesday, Skakel's attorneys filed more than 100 pages of documents, including allegations that Skakel was abused by his father and nannies. The defense said he had overcome a difficult upbringing to lead an exemplary life and should receive leniency.

One of the letters was from Skakel's cousin, Robert F. Kennedy Jr.

"During his short life, Michael has endured unusual suffering," Kennedy wrote. "He was a small, sensitive child -- the runt of the litter with a harsh and occasionally violent alcoholic father who both ignored and abused him."

Instead of becoming bitter, Skakel used the experiences to help others, according to Kennedy, who credited Skakel with helping him get sober.

Defense attorneys say Skakel's father beat him so frequently that he often slept in his closet, and say his father once fired a rifle at him while they were hunting.

The death of Skakel's mother in 1972 from cancer prompted his father to drink more, worsening his abusive behavior toward his children, a defense motion contended.

Nannies hit Skakel and his brothers with spoons and pots, according to Julie Skakel, his sister.

"Many times these nannies locked the children in their rooms as the locks were on the outside of the doors," the motion states.