Wednesday is sentencing day in State Superior Court in Norwalk, Conn., for Michael Skakel for the 1975 murder of Martha Moxley, but the New York Times reports that Skakel’s lawyers have intensified their efforts to win him a new trial. The paper says Skakel’s defense team intends to accuse prosecutors of withholding a police sketch and other information that they claim would point the finger at another suspect. (Skakel, 41, is expected to be sentenced to 10 years to life, NBC News reports.) On June 7, a jury convicted Skakel, a nephew of Robert F. Kennedy’s widow Ethel Kennedy, of fatally bludgeoning Moxley with a golf club outside her family’s home in Greenwich, Conn. They were both 15 at the time. In court papers filed Monday, the defense focused on a sketch of a white man in his 20s or 30s, wearing thick, round-rimmed glasses and who was seen walking near the murder scene by a security guard. Skakel’s legal team wrote that the sketch “bears a striking resemblance to Kenneth Littleton,” a tutor for the Skakel family. The lawyers insist that Littleton was “the probable killer,” which, they say, did not come out during Skakel’s trial.