For months, Michael Guzzo complained to neighbors about incessant dog barking, even putting up fliers on doors throughout his Phoenix townhome complex advising people of pet ordinances and fines.
This weekend, police say, Guzzo went on a rampage, methodically killing four members of a family and their two dogs that lived next door before killing himself with the same shotgun.
While his motive died along with him, neighbors and family members of the victims say he was becoming increasingly unhinged over dog noise.
Neighbors in the complex of two-story townhomes where a central courtyard looks like a tree-laden park said Guzzo made no secret that the barking dogs were irritating him.
He often left printouts of the city's dog barking ordinance on doors throughout the community, said Joni Flood, 21, who lives a few doors down from the victims.
"He hated them. But everyone here has dogs," Flood said.
Killed in the Saturday shooting were Bruce Moore, 66; his daughter, Renee Moore, 36; her husband, Michael Moore, 42, who used his wife's last name; and Renee's son, Shannon Moore, 17.
Family members of the victim were in shock Monday as they walked into the crime scene for the first time since the killing, standing amid pools of drying blood on the home's back patio where the two men were apparently killed first.
"It's angering beyond belief," said Patrick Riley, 41, Michael Moore's brother. He found his brother's silver necklace amid the blood. "It just angers me looking at all this because I just feel for my brother. The helplessness."
The patio wall was chipped with pockmarks from the shotgun's blast. Police haven't given specific details of the attack, but Riley said he thinks Guzzo shot his brother over a 6-foot cinderblock fence while he worked on a car engine.
"He had no idea what was coming," Riley said.
He said police told him Guzzo, 56, killed the two men first, then walked through the family's unlocked front door and shot Renee, her son, Shannon, and the dogs.
Phoenix Sgt. Steve Martos said authorities can only speculate on a motive for the killings.
"If he had left a note, maybe, but nothing like that occurred in this case," Martos said Monday.
Michael Moore's mother Jacque Alderman, 70, said Renee "told me all the time the man was crazy. He just couldn't stand the dogs."
Libni Deleon, 26, said that just a few months ago he returned home from work to find Guzzo standing by his back gate where his two dogs were on the patio barking.
"He said, 'Your dogs are barking. I'm here to live in peace,'" Deleon recalled.
Deleon says Guzzo tried to kill him on Saturday, too.
Moments after the shooting, Guzzo walked across the courtyard and began kicking on their front door.
Libni Deleon's wife, Vanessa, had just gotten out of the shower, grabbed their two children and ran upstairs to hide in the bathtub.
Libni went toward the door as Guzzo blasted two holes through it, sending about 20 shotgun pellets into the walls at the back of their home.
He ran upstairs to get his own gun, opened the window and began to yell at Guzzo, who opened fire again before walking back to his home to turn the gun on himself.
"I feel pretty darn lucky," Libni Deleon said.