A 14-year-old boy accused in a triple-murder on newsman Sam Donaldson's (search) ranch told police he took a gun from the barn and shot his family after being repeatedly beaten by his father — including once with a shovel, according to a man who took care of the teenager before his arrest.

Cody Posey (search) remained in custody Thursday in the deaths of his father Delbert Paul Posey, stepmother Tryone Posey and 14-year-old stepsister Mary Lee Schmid, whose bodies were unearthed from a shallow grave near their home on the southern New Mexico ranch.

In an exclusive interview with the Associated Press, Faustino Salcido said he was present during questioning of Cody Posey by Lincoln County sheriff's deputies Wednesday.

Salcido, whose two sons are friends of young Posey, said the teen had stayed with their family Monday and Tuesday — playing basketball, frolicking in the river and shooting off fireworks — but said nothing about the slayings.

And the Salcidos suspected nothing because Cody "was all happy. We'd never seen him like that," Salcido said Thursday at his rural home about 15 miles from the Donaldson ranch.

"Before, he was real quiet and drawn away. He'd talk to you, but he wouldn't carry on a conversation. (Monday) you couldn't keep him quiet. He told me these were the happiest two days he'd had in his life ... he thanked me for letting him stay," Salcido said.

On Wednesday, authorities showed up and began asking Cody questions. Salcido said Cody didn't break down until deputies took him away, accompanied by Salcido, for additional questioning.

"That's when he started crying, saying he knew it was wrong but that the world would be better off without them in this world. He was tired of all this abuse," he said.

Salcido said the boy told investigators that on Monday "he was cleaning the corral, and his dad didn't like the way he cleaned it, so he smacked him a couple of times and told him to go into the house."

Salcido said the boy told deputies that he went into the barn, got the family's .38-caliber pistol and went into the house.

"His mom was in there. That's the one he shot first. Then the dad and the sister came in, and he shot them too," Salcido said the boy told investigators.

A probable-cause statement filed Thursday by the district attorney's office revealed details similar to those described by Salcido. It said the boy told deputies he buried the three victims in manure.

In Cody's bedroom at the ranch house, deputies found a note to police and clothing with what appeared to be blood stains, according to the statement.

Salcido also said the boy told deputies his father hit him with a shovel and tried to strangle him during the Fourth of July weekend. A pattern of abuse was well known to his sons and others in the community.

The sons told the AP they recalled many instances when Cody Posey showed up at school with black eyes and other bruises.

Lincoln County (search) Sheriff Tom Sullivan said authorities did not investigate any abuse in the family. He said if a teacher had reported it, "we would have done something about it."

A math and science teacher at Hondo Middle School (search) on Thursday described Posey as a top student and "rambunctious." Roman La Riva, who taught Posey for three years, said he never saw any physical abuse but had the impression from parent-teacher meetings that Cody's parents were "constantly coming down on him."

Donaldson, encountered Thursday by a reporter at the Hondo post office, told the AP he had never witnessed any abuse nor heard of any against the boy.

Earlier, speaking on ABC's "Good Morning America," Donaldson described the Poseys as "the all-American ranch family." He said the couple were hard workers, the daughter was a "sparkler" and Cody was quiet and respectful to him.

Donaldson also said: "Paul was a little hard on his son, but that's the way ... you raise young men. I never saw Paul raise his voice or his hand in anger to his son. He clearly expected a lot of him."

Assistant prosecutor Sandra Grisham of Alamogordo said formal charges would be filed Friday against Cody Posey, who was being held in an Albuquerque juvenile facility.

District Attorney Scot Key said the boy could face adult penalties, including up to 30 years in prison, if convicted.