Connecticut prosecutors say Kennedy cousin Michael Skakel's 2002 murder conviction was based on compelling evidence and was not the fault of his trial attorney.

Skakel argues the case was weak and that trial attorney Michael Sherman failed to competently defend him when he was convicted of killing his Greenwich neighbor in 1975, when they were 15. Skakel is serving 20 years to life for the golf club bludgeoning of Martha Moxley.

Skakel is the 52-year-old nephew of Robert F. Kennedy's widow, Ethel Kennedy.

Prosecutors filed court papers last week and Skakel's attorney filed them last month. A judge is expected to rule by December on whether Skakel deserves a new trial.