PORTLAND, Maine — Defense attorney Daniel Lilley told jurors on Monday that the first words 72-year-old Merrill Kimball uttered after he shot and killed Leon Kelley at Brown’s Bee Farm in North Yarmouth on Oct. 6, 2013, were, “What was I supposed to do? He came at me. I’m 70 years old.”

“That’s really our defense,” Lilley said early Monday afternoon as the murder trial of Kimball got underway after a delayed jury selection process.

Kimball, a Yarmouth lobsterman, is charged with murdering Kelley, 63, of Georgetown at the well-known bee farm. But Lilley told the jury on Monday that Kelley provoked the confrontation and Kimball shot him in self-defense.

The defense and prosecution acknowledge that Kimball’s gunshots resulted in Kelley’s death, but they disagree on the circumstances that led to the shooting.

Lilley showed the jury — six women and eight men of varying ages — an oversized image of Kelley’s driver’s license, which lists him as 6 feet, 4 inches tall and weighing 255 pounds — “although the autopsy showed it was more like 295,” Lilley said.

According to Lilley, after knee surgery earlier that year, the shorter, slighter Kimball was unable to run when Kelley allegedly approached him, put his hands on Kimball’s shoulders and turned him around, telling him to get off the property.

Lilley said witnesses would testify that Kelley “kept coming toward [Kimball] and [Kimball] kept backing away … he was retreating, but he couldn’t retreat any further … a much bigger man was coming at him with evil intentions.”

Assistant Attorney General Matthew Crockett said Kimball was not acting in self-defense when he pulled out a .380 semi-automatic Ruger handgun “and assumed a shooting stance, aimed at Mr. Leon Kelley and pulled the trigger not once, not twice, but three times.”

Kelley was shot twice in the torso and one time through his arm into his abdomen. He died in an ambulance on the way to Maine Medical Center that day.

“This was not a kill-or-be-killed situation,” said Crockett, who is prosecuting the case with Assistant Attorney General John Alsop. “The defendant could have walked away in multiple directions. Common sense and reason will tell you the defendant did not act in self-defense.”

Crockett told the jury that Karen Thurlow-Kimball, the defendant’s wife, met Stan Brown, a well-known Maine beekeeping expert, in 2009 and began a business relationship focused on bees. In the fall of 2013, Crockett said, that relationship “really began to sour” after members of Brown’s family began to suspect she no longer was looking out for his interests.

Crockett said that the day of the shooting, Stan Brown’s grandson Craig Rawnsley called Thurlow-Kimball and “told her things were going to change at his grandfather’s house.”

He said Merrill Kimball, in a gold minivan, along with Thurlow-Kimball and her son Damon Carroll in a red pickup truck, drove to the farm in order to get at least 10 five-gallon buckets of honey that she said were hers.

“They entered the property at a high rate of speed, according to witnesses, who saw Mr. Kimball driving and he appeared to be angry,” Crockett said.

When Kimball emerged from the car, Crockett said, Kelley introduced himself and extended his hand.

No punches were thrown or blows struck, Crockett said. Instead, “the state will prove that the defendant overreacted, being in no danger of death or serious physical injury … the defendant pulled out a handgun and he shot Leon Kelley … three times in rapid succession with no pauses.”

Falmouth communications dispatcher Marcia Gilpatrick was the prosecution’s first witness, and the jury heard a tape of the 911 call Gilpatrick took from Leon Kelley’s wife, Kathleen Brown-Kelley.

Brown-Kelley told Gilpatrick during the frantic call that she was at the home of her father, Stan Brown, then 94, and that Karen Thurlow-Kimball and Merrill Kimball and her son were on the property and “wanted to take stuff that didn’t belong to them.”

Suddenly, Brown-Kelley allegedly cried, “Oh, they just shot my husband. Oh my God … they’re killing my husband,” according to the 911 recording played for the jury on Monday.

But Lilley said that before the shooting, Kimball, his wife and her son “were being assaulted, almost simultaneously, and they did not lift a hand.”

Lilley urged the jury on Monday not to make any decisions until they had heard from both sides, and asked them not to consider a lesser manslaughter charge as an acceptable compromise to the murder charge.

“[This is] a death that is haunting him and giving him sleepless nights,” Lilley said of Kimball. “He is so sorry, but he had no choice.”

The trial is expected to continue throughout the week.