An eight-year-old boy accused of murdering his father and another man was to appear in an Arizona court on Monday in a case that has shocked police and prosecutors.
  
The boy is alleged to have gunned down the two men, his 29-year-old father and a 39-year-old co-worker in the small rural town of St Johns, 170 miles (273 kilometers) northeast of Phoenix last Wednesday.
  
Police responded to the boy's home minutes after neighbors called in the evening. The boy appeared at a neighbor's home and said he "believed his father was dead," according to St. Johns police.
  
The boy was charged with two counts of premeditated murder after confessing to police. He is scheduled to appear in court on Monday, the same day a funeral mass will be held for his father and father's roommate.
  
"This is precedent-setting. We're going to charge an eight-year-old with two counts of homicide," Police Chief Roy Melnick was quoted by local media as saying at the weekend.
  
Local prosecutor Criss Candelaria said the case was unprecedented.
  
"We haven't had anything like this in Apache County in my 23 years as a prosecutor," Candelaria told the Arizona Republic newspaper.
  
"We need to figure out what was going on in this boy's head."
  
A judge Friday ordered a psychological evaluation of the boy, who is being held in a juvenile detention facility.
  
The boy's father and his roommate were construction workers at a power plant being built near St Johns. He had full custody of his son.
  
The boy's biological mother visited St Johns from Mississippi last weekend and returned to Arizona after the murders, according to Apache County deputy attorney Brad Carlyon.
  
Carlyon said the boy has never been in trouble before, and has no disciplinary record at school.