BOSTON (CBS/AP) — A man convicted of killing a Boston police detective in 1993 has been granted a new trial.

Sean Ellis was convicted of first-degree murder for shooting Detective John Mulligan five times in the face while he slept in his car while on a security detail in September 1993.

A Suffolk Superior Court judge on Tuesday granted Ellis’ motion for a new trial, because authorities withheld information from Ellis’ trial lawyer.

“It’s devastating. It’s disappointing,” said Det. Mulligan’s brother, Richard Mulligan. “You think it’s all done with and then it just comes up again.”

Ellis’s attorney, Rosemary Scapicchio, says the information withheld included the alleged involvement of Mulligan and other officers in an armed robbery.

“Everything the Boston Police did were suspect,” Scapicchio said.

Ellis was convicted at his third trial following two hung jury trials.

He is serving a life sentence.

The Suffolk district attorney’s office says it “strongly disagrees” with the decision to vacate Ellis’ conviction and is reviewing its options.

Richard Mulligan said he is certain police arrested the correct suspect in his brother’s murder.

“Sean Ellis is the man. They got it right the first time. They worked hard on it the first time, the police and the DA. He was guilty,” he said.

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