The parents were away and returned home to find their house in disarray after a party that apparently included drugs, Franklin said.
The father called the sheriff's department on Sunday afternoon, and an officer arrived at the house to find that the father had handcuffed the son.
"They obviously were trying to discipline their son, and they had had problems with him in the past," Franklin said.
The deputy talked with the family and collected evidence from the party remnants that included a pipe used to smoke marijuana, Franklin said. The father told the deputy he planned to sign a juvenile warrant the next morning against the teen.
The deputy left on another call, but a neighbour called about 30 minutes later to say the teen showed up claiming his parents were fighting, Franklin said.
A deputy went back to the house and found Mike Holton dead of a gunshot wound to the head and the woman near death, also from a head wound; she died at a hospital on Monday evening.
The youth's description of what happened - that his father shot his mother during an argument and then turned the gun on himself - didn't match physical evidence, Franklin said.
A forensics examination determined the man's wound wasn't self-inflicted, he said, and preliminary investigation showed the woman's wound wasn't, either.
"We asked him if anyone else had been at the house and he said 'No'," said the sheriff.
The youth, a student at Elmore County High School, told detectives he gets "easily agitated" if he doesn't have access to marijuana and Adderall, Franklin said, and witnesses told investigators the teen has anger problems.
"He hasn't shown any emotion at all. Most people would be bawling their eyes out if their parents had been killed," said Franklin.
The couple's two younger children are with relatives, said Franklin.
- Additional reporting: AP
