Brice McMillan told deputies the boy was released the following morning, but was tied up again that night for bad behavior, according to the AP.
According to arrest warrants for the couple, the boy sustained "bruising to the wrist, cuts to entire body, missing flesh from buttocks, results from being tied to a tree for approximately 18 hours, resulting in death."
He was found unresponsive by his stepmother Thursday afternoon. She began CPR and alerted the police, but the teenager was pronounced dead on arrival after he was taken to the hospital.
"There are people who abuse their children in a frenzy of rage," said James Garbarino, forensic psychologist at Loyola University and author of "Children and the Dark Side of Human Experience."
"People do stuff beyond what is characteristic for them. There is a burst of intensity, frustration and anger. They simply lose control," he said.
Welner said parents can sometimes become overwhelmed by their own inability to manage a situation.
"People who manage their anger are not a danger to children," he said. "People who cannot and become overwhelmed are a danger.
"Abusive parents believe they are disciplining their children," he said. "They become increasingly angry with a child for not responding to discipline. Discipline becomes increasingly destructive as the parent comes to interpret the lack of responsiveness by the child as acting out against them."
On Friday, the mother of a 5-year-old Los Angeles boy was arrested by police who found countless cigarette burns all over the child's body, including his genitals. The boy was unable to open his hands because he had been forced to put them flat on a hot stove, and was repeatedly beaten and forced to sit in his own urine, according to Los Angeles police.
"In my time in policing in 27 years, I have never seen anybody with these kinds of injuries that has lived," L.A. police department First Assistant Chief James McDonnell said. "And this kid must have a tremendous will to live to be able to still hang on, despite what he's been through."
The boy's mother, Starkeisha Brown, 24, was arrested after she turned herself in to police on Friday evening.
Krystal Matthews, 19, who police described as Brown's live-in girlfriend, was arrested earlier Friday when she showed up for an appointment at the state Department of Children's Services with another child she claimed was the boy, police said.
The boy was hospitalized in critical condition, officials said over the weekend.
The experts consulted by ABC News.com called this long-term abuse "premeditated."
"There are people whose thinking and feeling becomes so distorted it is as if they live on another planet or dimension," Garbarino said. "If you ask them about their reason for abuse, they can give, what seems to them, rational coherent narrative. The account seems totally bizarre to you, but to them it seems like a coherent story."
According to Welner, "Rather than seeing a child as vulnerable and immature, the parent sees the child's lack of response to discipline as a source of his own failure. This behavior is premeditated and reflects increasing vindictiveness."
The extreme nature of these cases makes them stand out, but according to federal statistics, nearly 1 million children are abused in the United States every day.