"I failed him:" Nine-year-old boy left home alone while sister went to work mauled to death by her dogs

LINDA, California -- A nine-year-old boy left at home while his sister went to work was mauled to death by her dogs.

Neighbors say Alexandria Griffin-Heady recently moved into a small trailer in Linda, California.

Neighbors say she wanted to better her life, and eventually pull her little brother out of the foster care system. But on Sunday morning, January 3rd, investigators say she left him home alone with her three pit bulls.

Nine-year-old Tyler Trammell Huston was killed.

"With the circumstances -- of Ally not being mature enough -- not able to handle a nine-year-old. She's just barely 24 -- 25 herself," Donald Thorpe, the boy's uncle said.

Thorpe says the boy lived a hard life. He was in and out of foster homes after his mother died of a drug overdose -- homeless on the streets of Sacramento.

Thorpe says the boy's sister recently moved into the trailer in California from Florida. She got approved for weekend visits with her brother with the goal of later adopting him.

She returned from work on Sunday to find her little brother mauled to death.

"It was just a horrific, tragic accident," Stephanie Harvey, Alexandria Griffin-Heady's adoptive mother said. "She changed her life, gave up everything to do that for him. You can't even imagine what shes going through. You have no idea."

Griffin-Heady was too distraught to come out of her trailer on Monday and talk about what happened.

Investigators say she is cooperating. They say she could face child endangerment charges in this case.

But even for investigators, the details of this case don't sit well.

"I don't know. This one seems to have affected me most. The child being home alone and just had to have been terrified of what took place," Jerry Read, Yolo County undersheriff said.

Neighbors say what happened makes no sense.

"She was always very pleasant -- a very nice person," Dewayne Daniel said.

Daniel says the last time he looked over his neighbor was playing with her dogs.

Now, there's a sign out front reading "family in mourning."

The pit bulls were taken from the trailer and are now with animal services. Investigators say they will likely be euthanized.

FOX 40 in Sacramento spoke with Alexandria Griffin-Heady, the nine-year-old boy's half-sister and owner of the dogs.

"I failed him, whether it's my fault, my dogs' fault, whoever's fault. I wanted to protect him, and I wanted to give him an amazing life," Griffin-Heady told FOX40.

Griffin-Heady said she never thought what happened with her dogs would happen.

"He loved them. He laid in the bed with them. He played with them. He wanted one of their puppies," Griffin-Heady said.

Griffin-Heady said her goal was to get her brother out of the foster care system.

"His only wish for Christmas was to have a mom, I so badly wanted to be that person for him," Griffin-Heady told FOX40. "He'll never get to drive a car. He'll never get to have a first kiss. He'll never get to graduate. He wanted to be a zookeeper you know? He loved animals. And it kills me he'll never get any of those."

Yuba County Sheriff Steven Durfor told FOX40 before Sunday there were no other calls to the home for problems with those dogs.