RALEIGH, N.C. — North Carolina’s highest court on Friday left intact a murder conviction that a lower appeals court had thrown out on the grounds that a jury shake-up during deliberations violated the defendant’s rights and required a new trial.

By a 5-2 decision, the state Supreme Court reversed last year’s decision of a state Court of Appeals panel that had sided with Eric Ramond Chambers, who has been serving a sentence of life in prison without parole.

The state constitution says no one can be convicted of a crime except by “the unanimous verdict of a jury in open court” that state justices have declared in the past repeatedly must be composed of 12 people.

A 2021 state law says an alternate juror can be substituted for one of the 12 after deliberations begin as long as the judge instructs the amended jury to begin deliberations anew. The judge at Chambers’ 2022 trial did just that when an alternate juror joined deliberations because an original juror couldn’t continue the next day due to a medical appointment.

The original 12 had deliberated for less than 30 minutes the day before. Chambers, who was representing himself in the trial, was not in the courtroom when the substitution occurred. By midday the reconstituted jury had reached a verdict, and Chambers was convicted of first-degree murder and a serious assault charge for the 2018 shooting in a Raleigh motel room.

Chambers petitioned the Court of Appeals, which later ruled that his right to a “properly constituted jury” had been violated and the 2021 law couldn’t supersede the state constitution because 13 people had reached the verdict. State attorneys then appealed.

Writing for Friday’s majority, Chief Justice Paul Newby said the 2021 law doesn’t violate Chamber’s right because it provides “critical safeguards that ensure that the twelve-juror threshold remains sacrosanct.”

Newby wrote the law says no more than 12 jurors can participate in the jury’s deliberations and that a judge’s instruction to begin deliberations anew means “any discussion in which the excused juror participated is disregarded and entirely new deliberations are commenced by the newly-constituted twelve.”

The four other justices who are registered Republicans joined Newby in his opinion.

In a dissenting opinion to retain the new trial, Associate Justice Allison Riggs wrote the 2021 law is an unconstitutional departure from the concept of 12-member juries and “endangers the impartiality and unanimity of the jury.”

No matter what directions a trial judge gives to jurors to begin deliberations anew, Riggs added, “we must assume by law that the original juror’s mere presence impacted the verdict.”

Associate Justice Anita Earls — who with Riggs are the court’s two registered Democrats — also dissented.