PHOENIX – Police on Sunday to try to piece together what sparked a shooting at a Phoenix apartment complex that left five people and two dogs dead.

Sgt. Tommy Thompson said 56-year-old Michael Guzzo apparently killed himself after shooting four members of a family who lived in an apartment next to him. The family’s two dogs also were killed.

Thompson said police are still investigating why the killings happened.

Thompson said in a statement that a shotgun, which is believed to be the weapon used in the attack, was found next to Guzzo in his apartment.

The victims were identified as 66-year-old Bruce Moore, 42-year-old Michael Moore, 36-year-old Renee Moore and 17-year-old Shawn Moore.

Thompson said that Guzzo, after shooting the family, walked across the courtyard of the apartment complex and shot at the door and window of another townhouse before returning to his home.

“We woke up, somebody just banged on our door and they shot four rounds. I guess it was a shotgun, there’s big old holes on my door,” Libni DeLeon told Phoenix television station KSAZ (http://bit.ly/1a8DGFH ).

Another neighbour said Guzzo usually kept to himself.

“I’ve seen him every morning — come in quiet every morning,” Donald McKenzie told KSAZ. “Never would expect him to be the guy who did this at all.”