(CNN) -- A 10-year-old Arizona boy who admitted to shooting and killing his father and another man in 2008 was sentenced Thursday to "in-patient treatment" that could go on for several years, according to the prosecutor.
The boy pleaded guilty in February to one count of negligent homicide in exchange for a plea deal that dropped the two counts of murder he was charged with initially.
The boy was accused of killing his father, Vincent Romero, 29, and Tim Romans, 39, who rented a room in Romero's home in St. Johns, Arizona. Both men were found dead at the home November 5, 2008, and police said the next day that the boy confessed to shooting them with a .22-caliber weapon. At the time, the boy was 8.
"Under the plea agreement, he can be there (in treatment) up until he is 18," Apache County, Arizona, Attorney Michael Whiting said after the sentencing. "We hope that the treatment won't take that long. Obviously, it's not going to be successful if he is there when he is 18, and they are still treating him."
Whiting did not specifically describe what type of treatment the boy will undergo, beyond saying a psychiatrist will be involved and that the youth will be kept at his treatment facility with no ability to leave.
The judge in the case ordered follow-up evaluations of the boy every two and a half years to update court officials on his progress.
Defense attorney Ron Wood said the boy was upset and crying in court during the sentencing and, "He was frightened." The boy apologized and "accepted responsibility for what he did," Wood said.
During a news conference after the sentencing, Wood was asked how confident he is the treatment will work for his client.
"I don't know, ask me in three years. Ask me when he's been through the process of having his brain picked ... then maybe we will find out," Wood said.
Asked the same question, Whiting replied, "50-50 ... I would bet it's going to be a tough road."
Earlier, Whiting said, "There is not a question of who committed this crime. The question becomes, how does society and the court system deal with this crime."