Aza Ray Vidinhar, who was 15 when he stabbed his brothers, pleaded guilty in juvenile court to killing his 4-year-old brother and in adult court to the murder of the 10-year-old. His lawyer, Todd Utzinger, said he will remain in a juvenile detention facility until he is 21 or until officials decide he can no longer be helped there.
"Without the opportunity and benefit of treatment, it would be my opinion that it's inhumane to send him to prison," Utzinger said during the second hearing.
Utzinger said the agreement calls for Vidinhar to be re-sentenced when he leaves the juvenile system to 15 years to life. He can then apply to the Utah Board of Pardons and Paroles for a review, with "his conduct and his performance while in juvenile detention" likely to be a major factor in whether he wins release.
The teenager's parents watched during the hearing as he admitted the killings, sometimes wiping their eyes.
Vidinhar's mother found the 4-year-old's body in the family home in West Point on May 22, 2013. Police discovered the 10-year-old in another room.
Vidinhar was arrested after he was found walking about 8 miles away. He was subjected to lengthy interrogation, and the prosecutor has said any statements he made cannot be used.