US: Michael Skakel has appealed to the US Supreme Court to overturn his conviction for the 1975 murder of a 15-year-old neighbour, arguing that the statute of limitations had passed when he was charged with the crime.
Skakel (45), was charged in 2000 and convicted in 2002 of beating Martha Moxley to death with a golf club when they were both 15. The nephew of Robert Kennedy's widow Ethel, Skakel is serving 20 years to life for the murder.
He appealed his conviction to the Connecticut Supreme Court last year, arguing that a five-year statute of limitations, in place in Connecticut at the time Moxley died but abolished a year later, had expired when he was charged in 2000.
The court unanimously rejected that appeal in January.
"The state of Connecticut's retroactive application to Mr Skakel of a statute of limitations that the State's highest court had twice held did not apply to cases such as his, violated his constitutional right to due process under the law," Skakel's lawyer Theodore Olson said.
Mr Olson said that if the Supreme Court agreed to hear the case and Skakel prevailed on his statute of limitations argument, prosecutors would be barred from trying him again for Moxley's murder.