A prosecutor urged the state Supreme Court on Tuesday to deny a new trial for Richard Lapointe, a brain-damaged man whose supporters have been trying for two decades to win his freedom on claims he was wrongfully convicted of killing his ex-wife's 88-year-old grandmother.

Assistant State's Attorney Timothy Sugrue told the justices they should overturn a ruling last year by the state appeals court that granted Lapointe a new trial after concluding the state failed to give Lapointe's lawyers evidence that may have supported an alibi defense during his 1992 trial.