Police officer: Deadly game of hide-and-seek

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ATLANTA (CNN) -- A 15-year-old girl and her 10-year-old brother face murder charges after confessing to killing their 6-year-old brother near their rural Texas home.

Lewisville Police Officer Richard Douglass discussed the case Tuesday with CNN's Kyra Philips.

CNN: Start with background on what happened last night. It started with a game of hide-and-seek I understand.

DOUGLASS: Yes. The police received the call from the parents about 6:45 p.m. last night that the child was missing after a hide-and-seek adventure with his older brother, the 10-year-old.

CNN: So you interviewed the 10-year-old brother and 15-year-old sister and did they come right out and confess to this? How did the interview process go?

DOUGLASS: I know that our officers, the investigators, the team of police officers that were in the house, they had been in the house since around 6:45 p.m. last night.

And during the investigation an interview processed at that time led them to discover the boy's body when the 15-year-old sister admitted to the investigators she had killed her brother and led them out about 100 yards southeast of their house where the body was in a shallow grave of mud, water and debris.

CNN: Did she say why?

DOUGLASS: The motive is under investigation. That's not released yet, whether she told investigators that at this time or not. The 10-year-old did have a conversation with our investigators and said that when he was detained that he admitted to helping his sister hold the brother down until he was dead.

CNN: Have they been charged in the death?

DOUGLASS: Last night they were in front of a magistrate at the location and the police shortly after that took him into custody and did transport him to the Denton County juvenile detention center under the charge of murder.

CNN: What can you tell us about that 15-year-old her emotional state right now?

DOUGLASS: The investigators had interviewed, for six or seven hours while the search was going on, a multitude of people out in the field and out in this rural area looking for this young boy, not knowing he was dead, but in fact thinking he was hiding or lost.

And during that time both children or both the sister and brother didn't say much to police until late in the evening almost 12:00 or 12:30 when the signal come up there might be a way the 15-year-old could point out where brother was. That's when she told the investigators she had killed him and led out to the grave site.

CNN: Where were the parents at the time?

DOUGLASS: The parents were at the house during the whole time during search last night. They were concerned about where the boy might be as everybody was.

CNN: Have the parents been interviewed about the relationship among the three kids?

DOUGLASS: Yes the interviews and investigation are ongoing as we are speaking now. The family is traumatized quite a bit. They have three children. One is deceased and two are in the detention center. We interviewed them last night and the investigation, as I mentioned, is ongoing and they will [be] interviewed and talked to again later on, either today or tomorrow.