New Mexico shooter planned more

Photo: The Canadian Press. All rights reserved.

A bouquet of flowers adorns the entrance to a home on Monday, Jan. 21, 2013, where a couple and their three young children were found shot to death south of Albuquerque, N.M. The couple's 15-year-old son, Nehemiah Griego, is facing counts of murder and child abuse in connection with the shootings. (AP Photo/Susan Montoya Bryan)

A U.S. teenager accused of gunning down five family members over the weekend ambushed his father as he returned home from an overnight shift at a rescue mission, then reloaded his rifles and planned to go to a Wal-Mart and randomly shoot people, authorities said Tuesday.

Instead, 15-year-old Nehemiah Griego texted a picture of his dead mother to his 12-year-old girlfriend, then spent much of Saturday with the girl and her family, authorities said. That evening, he went to church where Griego's father had been a pastor, and Griego eventually confessed to killing his parents and three younger siblings.

"The motive, as articulated by the suspect, was purely that he was frustrated with his mother," Bernalillo County Sheriff Dan Houston said. "He did not give any further explanation."

Houston said Griego had planned the shootings for at least a week, but it's unclear if he ever actually went to a Wal-Mart or why he changed his mind about continuing the attack, which occurred on the same day thousands of gun advocates gathered peacefully at state capitals around the country to rally against stricter limits on firearms. The "Guns Across America" events were being held just after President Barack Obama unveiled a sweeping package of federal gun-control proposals.

A series of mass shootings -- especially an elementary school attack in Connecticut last month that left 20 young children and six adults dead -- have fired up the debate over gun control in the U.S.

While many Americans support stricter gun legislation, many others are fiercely opposed, considering it an assault on the Second Amendment of the Constitution that guarantees the right of citizens to bear arms. Obama's proposals include a ban on assault weapons of the sort used both in the New Mexico and Connecticut shootings, but the idea is expected to face stiff support from congressional Republicans, who control the House of Representatives.

Griego told detectives he also contemplated killing his girlfriend's parents, Houston said.

The sheriff said he didn't know if Griego's contact with his girlfriend avoided further bloodshed. But he said she apparently knew what had happened, and officials are investigating whether she should be charged with failing to report the crime.

"We know Nehemiah had been contemplating this for some time," Houston told reporters at a Tuesday news conference. Griego apparently had told others of his plans, but whom and when was still under investigation, Houston said.

The teen waived his right to arraignment in adult court Tuesday on charges of murder and child abuse resulting in death and a judge ordered him held without bond. The case was assigned to public defender Jeff Buckels, who didn't immediately respond to a phone call seeking comment.

The sheriff's office identified the victims as Greg Griego, 51, his wife, Sarah Griego, 40, and three of their children: a 9-year-old boy, Zephania Griego, and daughters Jael Griego, 5, and Angelina Griego, 2. All appeared to have gunshot wounds to the head.

According to Houston and charging documents, it all began early Saturday at the family's home, when Nehemiah Griego -- angry and annoyed with his mother -- acted on what he described to investigators as homicidal and suicidal thoughts.

Houston said the teen shot his mother while she slept at about 1 a.m. with a .22 calibre rifle the parents kept in a closet. He said he killed his siblings after they woke up and became upset, then grabbed a military-style assault rifle his parents owned and waited in the downstairs bathroom to ambush his father as he returned from work at a rescue mission around 5 a.m.

Griego told authorities he then reloaded the two guns and put them in the family van.

Houston said he didn't know if Griego actually went to a Wal-Mart, but officers found the two rifles, as well as at least a dozen rounds for the .22 and a handful of rounds for the .223 calibre assault rifle in the van.