PHOENIX (AP) — For months, Michael Guzzo complained to neighbors about incessant dog barking in his Phoenix townhome complex, even putting up fliers on doors reminding neighbors of city pet ordinances

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 it was no doubt the dogs. They say he was becoming increasingly unhinged over dog noise in the complex.

Family members of the victims 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 two of the victims were killed first.