But police said what drove 56-year-old Michael Guzzo ofPhoenix to carry out the shooting frenzy may never be known forcertain, as both he and his victims, who ranged in age from 17to 66 and lived next door, were dead before officers arrived.
"It appears he had some issues with barking dogs," saidPhoenix police spokesman Sergeant Tommy Thompson. "If true, itdoes not justify killing four people."
Police found the victims slain after responding to a reportof gunshots at about 9:15 a.m. on Saturday in a downtowntownhouse complex, Thompson said.