The man at 12681 Poplar Street was Robert J. Price, a 52-year-old building inspector. He kept a .44 Smith & Wesson six-shooter in his bedroom safe.
The man at 12682 Taylor Street was Glen Ray Berry, a 53-year-old former truck driver. He liked to set off firecrackers in his backyard.
For a decade and a half they were neighbors in Garden Grove — separated only by a fence and a cinder block wall, a proximity both found increasingly intolerable as the years wore on.
Police became accustomed to the calls as the animus grew.
Berry complained that Price threw rocks at his property. Price complained that his bicycling 12-year-old son had been chased by Berry's car.
Berry complained that Price had threatened to put him in a body bag. Price complained that Berry spied on him and had concocted the fiction that he was a drug trafficker.
Late on the night of June 20, 2013, Berry lit a firecracker in the back yard, an act authorities say was meant to scatter the birds in his lemon tree.
A few hours later, Price — frustrated at his fitful sleep — retaliated by throwing his own firecracker into his neighbor's yard.
Roused from bed, Berry put on shorts, a tank-top and flip-flops and went over to pound on his neighbor's door.
Price answered. Then he lifted his .44 revolver and fired a single bullet through the steel mesh of his closed security door. The bullet obliterated Berry's right eye and passed through his head, killing him on the spot.
"I just shot my neighbor," Price told a 911 dispatcher. "I thought he had a gun."
Price is now on trial for murder, a charge that could send him to prison for life.
In her opening statement to jurors Tuesday in Orange County Superior Court, prosecutor Cynthia Herrera described the shooting as "the ultimate payback" for years of mounting frustration with his neighbor.
"There were years of bickering — 10, 12, 14, almost 15 years of it," the prosecutor said. "This was constant back-and-forth, back-and-forth."
The prosecutor acknowledged that Berry was "a nosy neighbor" and that both men at times had acted "like 12- or 13-year-old boys" throughout their feud.
She said that Berry was unarmed when he was shot, and that Price's statements to police were inconsistent. Price said Berry had swung his arm at him, even though the security door between them was locked, the prosecutor said.
Price's attorney, Doug Myers, said it wasn't murder but self-defense. He said the case was about a man's right to protect himself on the threshold of his own home.
Berry had stormed over to his neighbor's house and pounded so violently, Myers said, that Price feared he was trying to bust down the door.
"This is not someone who could fairly be described as calm," Myers said.
The defense attorney said Berry was angry and out of control and threatened to kill his client.
More than once in the year and a half before Berry's death, Myers said, Price's family had called police to say they thought they had heard their neighbor shoot a gun off in his back yard.
"Mr. Price believed he was in real danger," Myers said.