Story highlights Nephew of Robert and Ethel Kennedy was convicted in 2002 for killing a neighbor

Skakel can appeal the court's decision to reinstate his conviction

(CNN) Michael Skakel could be headed back to prison after the Connecticut Supreme Court on Friday reinstated his conviction in the 1975 murder of a 15-year-old neighbor.

Skakel, the 56-year-old nephew of Robert and Ethel Kennedy, had spent more than a decade in prison for the killing of Martha Moxley until a judge in 2013 decided he did not receive adequate representation in his trial and ordered a new one.

On Friday, after Skakel had been free for three years, the state's high court overruled the decision.

"Because we conclude that the petitioner's trial counsel rendered constitutionally adequate representation, we reverse the judgment of the habeas court and remand the case to that court with direction to render judgment denying the petition," the state's high court said in its decision.

One of Skakel's attorneys, Stephan Seeger, told CNN he was just becoming aware of the decision.

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