"Why'd you take it out on your little brother? Was it because he was there?" the detective asked.

"Yes," Fernandez said.

Fernandez, again using a doll, showed the detective how he shoved Galarriogo into the bookcase. He said the boy was bleeding from the nose and mouth, so he carried him to the bed.

"What was your mom doing when this happened?" the detective asked.

"I don't know," Fernandez said.

"Was she home?" the detective asked.

"No, she was driving, taking my other brother to school. I'm not sure where she was," Fernandez said.

"Does she make you babysit your brothers and sisters a lot?" the detective asked.

"Yes," Fernandez said.

He said after he shoved Galarriogo's head into the shelf two times, the boy didn't move but was breathing.

The detective leaves the room about 58 minutes into the recording, then returns about 12 minutes later. The two review things.

"Did you know what you did was wrong?" she asked.

"Mm, hm," Fernandez said. "I felt bad because then I realized what I'd actually done, because I really wasn't thinking about what I was doing when I pushed him. I was just thinking about myself."

He went on to say he was worried about what was going to happen to Galarriogo, that he wasn't worried about himself.

Fernandez asked if his brother didn't wake up, would that mean he won't make it. He asked if the doctors could wake him up. The detective said they couldn’t do that, and she didn't know what was going to happen.

Last year, Judge Mallory Cooper last year granted a defense motion to dismiss the videotaped interview and confession as evidence because police were wrong to interrogate him without another adult present -- that his consent as a 12-year-old was not legally sufficient.

Gene Nichols, a defense attorney not related to the case, says either way, the would likely have ended in a plea agreement.

"There's no question that by the judge tossing this, the judge had determined that this young man did not have the mental ability to understand what his rights were," Nichols said. "Whether or not the statements are consistent, we don't know, and we won't know unless we can ever find out physically what happened in that room."

Fernandez, now 14, will remain jailed until his 19th birthday.