BOSTON — Massachusetts’ highest court has overturned an order granting a new trial to a man convicted of killing a 10-year-old Boston girl while shooting at rival gang members.

The Supreme Judicial Court issued its decision in Joseph Cousin’s case on Thursday. The justices said a lower court was wrong when it ruled that an attorney for Cousin had an actual conflict of interest that warranted a new trial.

The SJC says the lower court must re-examine whether Cousin deserves a new trial, using a different standard.

Joseph Cousin was convicted of second-degree murder in the 2002 fatal shooting of Trina Persad as she and her siblings left a park in the Roxbury section of Boston.

Prosecutors said the girl was shot in the face with a sawed-off shotgun Cousin fired.