A judge made that ruling late Tuesday afternoon.
Prosecutors say the teens beat 37-year-old Regynald Jose Brown to death and stuffed his body in a trash can before attempting to bury it.
Brown's remains were found along a greenway path just south of downtown Raleigh last November.
In courtroom testimony at pretrial hearings, witnesses said the teens involved were members of a clique called "Big Money Swag," or "BMS."
According to testimony, BMS assaulted several homeless men. In one case, they made one of their victims eat feces, videotaped it, and showed it off to their friends.
In all, three 15-year-old boys were charged with murder. A 13-year-old boy was also charged with murder but was released in December after giving a statement to investigators. Another 15 year old has been charged as an accessory.
State law bars prosecutors from seeking the death penalty in murder cases where the defendants are younger than 18.