A 14-year-old boy was charged with killing his family a day after their bodies were found on a ranch owned by Sam Donaldson (search).

The teen, accused of slaying his father, stepmother and stepsister on the ABC newsman's property, was arrested on Wednesday at a friend's home in the Hondo (search) area around 5 p.m., Lincoln County Sheriff Tom Sullivan said.

The bodies were found at the ranch in south-central New Mexico (search) after Donaldson went to the manager's house on Tuesday and discovered an "obvious crime scene," Sullivan said. Deputies searched the area and found the three bodies in a shallow grave. No other details of the slayings were released.

The dead were identified as ranch manager Delbert Paul Posey, the teen's father; stepsister Mary Lee Schmid, 14; and stepmother Tryone Posey.

The teen was detained on three counts of murder and four counts of tampering with evidence. An initial court appearance was scheduled for Thursday, Sullivan said.

In a prepared statement, Donaldson said he and his wife, Jan, hired Paul Posey to work at the ranch in October 2001. "Jan and I are so very, very sorry about the loss of these fine people," he said.

District Attorney Scot Key said the teen would be tried in juvenile court but could face an adult penalty if convicted. He said punishment could range from probation under juvenile law to 30 years in prison, the standard sentence in New Mexico for an adult convicted of murder.

"We've never seen a triple murder, and the circumstances of a juvenile committing a crime against family members hasn't been experienced here," Key said.

The Donaldsons were in Santa Fe in northern New Mexico during the Fourth of July weekend, when the slayings apparently occurred.

"We didn't see them Tuesday morning or Tuesday afternoon, so I went over — and on the porch was a large stain that was instantly recognizable," Donaldson told Albuquerque television station KOB-TV. He then called the sheriff's office.

Donaldson described the teen as "withdrawn, like any typical teenager."

Donaldson's Lincoln County ranch is in rolling pastureland about 125 miles northeast of Las Cruces.

Donaldson, a journalist with ABC since 1967, owns three ranches in south-central New Mexico and has extensive ties to the state. He grew up on a cotton farm in New Mexico and graduated from New Mexico Military Institute in Roswell.

The Associated Press contributed to this report.