There was, at best, only a little speculation circulating Sunday about what might have set off Michael Dante Guzzo: Barking dogs next door, perhaps. Investigators couldn't really say.
But the rest of what happened at a townhouse complex in Phoenix was horribly clear.
Before 9 a.m. Saturday, Guzzo, 56, went to his next-door neighbors' townhouse with a pump shotgun and opened fire, authorities said.
The Moore family -- Bruce, 66, Michael, 42, Renee, 36, and Shannon, 17 -- were all shot dead. Guzzo killed Bruce and his son-in-law Michael on the back porch before going inside to kill Renee and her son Shannon, Phoenix police spokesman Tommy Thompson told the Los Angeles Times.
Guzzo also killed the family's two dogs, Thompson said.
"Three generations in one family were touched -- were destroyed because of this," Thompson said.
Afterward, Guzzo crossed a large courtyard and shot through the door of a different townhouse, police said; he also fired through a second-story window after somebody shouted at him.
Barry Hatchett, a neighbor, told ABC-15 he stepped outside after he heard a few gunshots.
"When I walked outside, I saw a middle-aged gentleman with a big shotgun in his hand -- had it thrown over his shoulder, actually," Hatchett said. "Then he spoke to someone across the way, and what he said was, 'You didn't think I seen you, homeboy?' Then he pumped the gun and he shot it."
Thompson, the police spokesman, added, "In retrospect, I'm convinced those residents had no idea that man had just killed four people."
Hatchett said Guzzo was walking back and forth and pumped the gun again -- but then, instead of continuing to kill, went home.
There he shot and killed himself with the shotgun, which was found next to his body, police said.
Hatchett called police after seeing Guzzo with the gun. Police stumbled onto the grisly scene at the Moore home while hunting for Guzzo.
"I've seen him every morning, come in quiet every morning. I've waved to him from that blue gate two or three times a week," a neighbor, Donald McKenzie, told a local Fox affiliate. "Never would expect him to be the guy [who] did this at all."
Thompson could confirm little more about Guzzo or his possible motives, noting that the man appeared to have little history with police beyond a driving-while-intoxicated arrest in the 1980s somewhere on the East Coast.
"There are questions we might never find the answers for," Thompson said. "He's the one that truly knows why he truly did what he did, and he's deceased. And the victims who could provide that information, they're deceased. … Right now, it's just absolutely senseless."
State records show a Michael D. Guzzo owning a one-man pharmaceutical LLC, PharmAZy Services, at an address on the same block where police said Guzzo lived. (Police wouldn't confirm whether Guzzo's address was the same address belonging to the LLC.) Guzzo's pharmacist license was set to expire in just a few days, on Oct. 31.
On an archived version of a business website registered under Guzzo's name and the same address, Guzzo described himself as a "pharmacist, individual investor, and Mexican-food junkie finding humor in even the worst of circumstances." The site was scrubbed sometime within the past two months.
Guzzo was also apparently the author of a small-time financial blog titled "Guzzo the Contrarian," which detailed his thoughts on the economy and his investment decisions. That site was registered to the same address as the business website.
But much of Guzzo the Contrarian was taken down sometime before last year, leaving only a final post from Feb. 5, 2012.
In that post, the writing takes on a harsh, suspicious edge. Guzzo said he had allowed himself to retire early after predicting the 2008 financial crash and staying out of debt. He blasted "average Joe investors" who were "incapable of independent thought ... doomed to follow the herd ... born followers who need someone else telling them how to lead their lives, regardless of how much they're being exploited."
Guzzo added, "Ironically, only the criminals on Wall Street and in the financial industry gave me any credibility, but they were profiting from my actions and opinions. So, I shut Guzzo the Contrarian down."
In a follow-up comment, Guzzo said he had his defenders -- but it's not clear who they were, or who was criticizing him. No one else ever commented on the post.