Siblings suspected in killing of brother, 6

LEWISVILLE, Texas (CNN) -- A 15-year-old girl confessed early Tuesday to killing her 6-year-old brother in a Texas town about 20 miles northwest of Dallas, and a 10-year-old brother also has been implicated in the death, a police spokesman said.

Investigators have not yet learned how or why Jackson Carr died, Lewisville police Officer Richard Douglass said.

The two older children, whose names were not released because they are juveniles, are in a juvenile detention center in Lewisville, Douglass said.

He said the two have been charged with murder, but it was unclear if they would be tried as adults or juveniles.

Douglass said the children's parents, Michael and Rita Carr, alerted police shortly before 7 p.m. CDT Monday that their younger son was missing. They had searched for the boy for about an hour and a half, he said.

CNN NewsPass VIDEO Authorities in the U.S. state of Texas say a 15-year-old girl and her 10-year-old brother have been implicated in the killing of their 6-year-old brother. KDFW's Brandon Todd reports (April 17) Play video   RESOURCES CNN Access: Deadly game of hide-and-seek

Nearly six hours later, the teen-age girl led investigators to the boy's body in a shallow, muddy grave about 100 yards from the family's rural home.

"She confessed to the murder, and then it was learned that the 10-year-old brother held down his brother while he died," Douglass said.

Douglass said the boy had a puncture wound on his neck when his body was found, but investigators said they did not know if it had contributed or was connected to his death.

The Carrs told police that Jackson had been outside playing hide-and-seek with the 10-year-old brother at about 5 p.m.

"The brother told him to go hide while he would count to 50," Douglass said. "The brother then came to his parents and said he couldn't find the boy after he stopped counting."

The Carrs searched for Jackson before calling the police, and by 10 p.m., about 60 people -- including police and fire department teams and civilians -- were combing the area with the help of search dogs, he said.

Douglass said he had not spoken with the parents but said he was certain they were "very traumatized and upset."

"Especially if you consider that as of 10 p.m. last night, they had three children, and as of 11:40 a.m. this morning, they have lost one and two others are in juvenile detention" he said.