ALBUQUERQUE (KRQE) - The 15-year-old boy accused in the horrific mass murder that left his father, a well-known chaplain, his mother and three younger siblings dead had been planning the crime for at least a week, sheriff's investigators allege.
The boy's preteen girlfriend also knew what he had done and may have known about his plans, but for now is not facing any charges, Bernalillo County Sheriff Dan Houston said at a news conference Tuesday.
Houston said Nehemiah Griego may have also plotted to kill his 12-year-old girlfriend's parents.
That young girl is now under investigation and could be facing charges.
Around 1 a.m. Saturday Griego allegedly shot his mother and three young siblings inside the family's South Valley home.
"The motive as articulated by the suspect is that he was purely frustrated by his mother," Houston said. "There is no best judgment from us.
"This is beyond any human reasoning or understanding at this time."
The sheriff also confirmed the boy sent a picture of his dead mother to his girlfriend.
The boy, armed with an assault weapon, then waited downstairs for four hours until his father, Greg Griego, returned home. The teen then shot his father multiple times before taking off in the family van with the AR-15, a .22-caliber rifle, two shotguns and extra ammunition.
Investigators say the teen spent much of Saturday, after the killings, with his girlfriend before heading to Calvary Church at about 8 p.m., 19 hours after first shooting his mother.
Around 9:15 p.m. BCSO was contacted by Vince Harrison, Head of Security at Calvary, who reported there were possibly multiple people dead inside the Griego home near Raymac and Coors.
Houston described the scene deputies found at the home Saturday.
"It's horrific. What other words do you use? This is certainly the first time I've been into a crime scene with this much destruction at one home," Houston said.
The Sheriff says the only possible motive Griego shared with detectives was that he was frustrated by his Mom. Although officials did say the teen may have been motivated by violent video games he played regularly.
At this time there is no indication of any mental illness, gang ties, drug or alcohol abuse on the boy's part and no claims of abuse against his parents.
Officials say there were four guns at the Griego home, all stored in the parent's bedroom closet which was left unlocked.
While Greg Griego had numerous arrests on his record and was a former gang member, deputies say he was not a convicted felon and had obtained the guns legally.
Later in the day Calvary Albuquerque announced a prayer vigil for the Griego family to be held at the church, 4001 Osuna Road NE, Wednesday at 7 p.m.
A Griego Family Memorial Fund also has been established with donations being accepted at New Mexico Educators Federal Credit Union branches.
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