Court documents claim 15-year-old shot mother and three siblings, then waited hours to ambush father.
New details have emerged in the slaying of a New Mexico family.
Court documents claim 15-year-old Nehemiah Griego confessed to taking a .22 caliber rifle from his parents' closet and shooting his mother, Sara, whom he was upset with.
He then shot his three siblings to death: 9-year-old Zephania, 5-year-old Jael and 2-year-old Angelina.
Griego told investigators he then waited five hours and ambushed his father, Greg, with an AR15 rifle.
"What brought that young man's mind to do this? It's got to be evil," said neighbor Terry Wootan.
Also disturbing is Griego's alleged confession of reloading the guns, putting them in his parents' van with the intention of driving to a populated area and gunning down more people.