Vincent Romero and his co-worker, Timothy Romans, were found dead inside Romero's home in the U.S. state of Arizona northeast of Phoenix on Wednesday, the ktar.com news portal said.
Police believe that both men were killed with a .22 hunting rifle by Romero's son, who is now facing charges of premeditated murder. Under Arizona law, a child under eight years old is a dependent child. However, charges can be filed against anyone above eight years old.
The boy, who is currently at a juvenile centre near his home in the town of St. Johns, "did not shoot on the spur of the moment," police said.
After the killings, the boy went to a neighbor and told him that he "believed that his father was dead." He later confessed to the killings, local prosecutors said.
Officers are investigating whether the boy could have been the victim of abuse.
