BANGOR, Maine — The Maine Supreme Judicial Court on Thursday considered the appeal of a local man convicted of murdering a rival in a street fight nearly three years ago.

Zachary Carr, 21, of Bangor was found guilty of murder and not guilty of manslaughter by a Penobscot County jury in March 2011. He was sentenced nine months later to 35 years in prison in the shooting death of John “Bobby” Surles, 19, of Bangor in a Jan. 27, 2010, street fight between two rival groups.

After Carr’s sentencing, Assistant Attorney General Andrew Benson, who prosecuted the case, confirmed that before the trial, Carr turned down an offer to plead guilty to manslaughter and serve less than 10 years in prison.

Bangor attorney Hunter Tzovarras, who did not represent Carr at his trial, is seeking a new trial because a recording of an interview with a key witness was not turned over to the defense team until after the trial. Tzovarras also argued in his brief filed with the court that the evidence was insufficient to sustain Carr’s murder conviction and to disprove his claims of self-defense.

“You can’t have murder trials when a key piece of evidence is not turned over to the defense,” Tzovarras told the justices. “It undermines the integrity of the legal process and undermines confidence in the verdict.”

Tzovarras did not argue that the 45-minute digital recording of a police interview with Jason Blake, one of two eyewitnesses to the shooting, was kept from the defense team on purpose. He conceded that the recording had been misplaced and was not found until after the trial.

Blake testified at the trial that he was being beaten by Surles with a mop handle when Carr kicked Surles, according to previously published reports. He told the jury that he was getting up off the ground when he saw a flash of light and heard the gunshot.

Justice Donald Alexander said if the recording had been available at the time of the prosecution, it would have been used by the prosecution to impeach Blake’s credibility as a defense witness.

“It would have been negative to you in the real world of a trial,” Alexander said.

Tzovarras disagreed. The attorney said the defense could have used the tape to refresh Blake’s memory since the recording was made the day after the shooting when his recollections were fresher than more than two years after the incident. Tzovarras also said it would have helped the defense team in its trial preparation.

“But the defense had something better than the recording,” Chief Justice Leigh I. Saufley said. “The defense had Mr. Blake.”

Tzovarras also challenged the length of Carr’s sentence on the grounds that Superior Court Justice Michaela Murphy should have given more weight to his client’s youth and should not have considered the use of a firearm as an aggravating factor.

Assistant Attorney General Donald Macomber said in his brief that Carr received a fair trial. The prosecutor, who handles murder appeals for the Maine attorney general’s office, also argued that Carr’s sentence was just.

Macomber wrote that the defense team had access to a summary of the witness’ interview with police even if they did not have a recording of it. He also argued that attorneys had the ability to interview the witness before the trial began.

“This was a planned gang fight and suddenly the gun comes out,” Alexander said. “Isn’t that manslaughter?”

“The jury determined it was murder,” Macomber told the justice.

Surles’ grandfather, Allen Suddy, 64, and his wife, Ann Suddy, 63, both of Bangor, attended the oral arguments. He declined to be interviewed on camera.

Everything that needs to be said was said at the trial,” said Allen Suddy, who also was Surles’ adoptive father. “He was found guilty of murder, not manslaughter.”

The court originally was scheduled to hear oral arguments in Carr’s appeal last month during its annual tour of high schools.

Bucksport High School Principal Dan Clifford was researching the case when he stumbled upon a Bangor Daily News story that mentioned police confiscating a gun outside the courtroom during Carr’s sentencing, according to a previously published report. The man in possession of the gun had allegedly waved an empty holster at Carr’s friends outside the Bangor courtroom.

“Our student safety is number one,” Clifford told the Bangor Daily News last month. “If there’s a case that’s questionable, we wouldn’t want to have it at the high school.”

Seeing that Carr’s case had caused concern before, Clifford contacted Mary Ann Lynch, government and media counsel for the Law Court, according to a previous story. The court subsequently decided to replace Carr’s case with another.

“There was no reason to take any risk when this case could just as easily be heard in November in a courthouse when the court is sitting in Bangor,” Lynch wrote last month in an email.

The Carr appeal was one of 11 the state’s high court was scheduled to hear over two days in Bangor.

There is no timetable under which the justices must issue their decisions.