PORTLAND, Maine — The Maine Supreme Judicial Court on Thursday considered whether a 73-year-old Yarmouth lobsterman’s murder conviction should be overturned in the October 2013 death of Leon Kelley, 63, at a North Yarmouth bee farm.

Merrill “Mike” Kimball, who is serving a 25-year sentence at the Maine State Prison in Warren, is seeking a new trial or to be exonerated and released. He was convicted by a Cumberland County jury in April 2015. Two months later, Superior Court Justice Roland Cole sentenced Kimball to the mandatory minimum for murder in Maine. The crime, under certain circumstances, can carry a life sentence.

In the appeal heard Thursday, Kimball’s attorney, Daniel Lilley of Portland, argued in his brief that Cole should have instructed the jury on the affirmative defense that Kimball acted out of extreme anger and had adequate provocation for his actions; excluded evidence that Kimball had been drinking the day he killed Kelley because there was no evidence Kimball was impaired; and admitted evidence there was a dispute over the will of Stan Brown, Kelley’s father-in-law, who owned the bee farm.

Lilley told justices Thursday that the defense team made a mistake by not asking for an adequate provocation instruction, which he claims was the judge’s most damaging error, until the day after Cole had given instructions and the jury had begun deliberating. If the justices agree, Kimball most likely would be retried.

The Portland attorney also said the jury should have found Kimball not guilty because the defense proved he acted in self-defense. If the justices were to find the jury came to the wrong conclusion, Kimball’s conviction could be set aside and he would be set free.

During six days of witness testimony, Lilley argued Kimball shot the much larger Kelley in self-defense after Kelley ordered him to leave the bee farm, then pushed him across the yard in a threatening manner, according to previously published reports.

To prove Kimball had adequate provocation to kill Kelley, Lilley would have had to show Kimball acted out of extreme anger or extreme fear, Justice Ellen Gorman pointed out Thursday.

“Didn’t your client induce this confrontation?” Justice Andrew Mead asked, referring to how Kimball drove “too fast” onto the gravel driveway, “spinning his tires” and demanded of Kelley, “Who the f—- are you?”

“No way,” Lilley responded. “Words never suffice.”

Assistant Attorney General Donald Macomber, who is handling the appeal, said Cole was right to reject the request for a jury instruction on adequate provocation because the facts of the case did not support it.

The central issue in this case was what was going through Merrill Kimball’s mind when he decided to pull out his gun and shoot Leon Kelley three times in his abdomen,” Macomber wrote in his brief. “[As] much as Kimball wanted to distract the jury away from this central issue by chasing down tangents about who would inherit Stan Brown’s farm when he eventually died, or about how Stan Brown felt about his family, or about how they felt about Karen Kimball [Merrill Kimball’s wife] the trial court acted well within its discretion by limiting that evidence to keep the jurors focused on the issues they would have to address — namely, whether Kimball intentionally or knowingly shot and killed Leon Kelley on Oct. 6, [2015,] and, if he did, whether he was legally justified in doing so.”

There is no timetable under which the justices must issue a decision.

BDN writer Beth Brogan contributed to this report.