JACKSONVILLE, Fla. -

As lawyers debate whether a 12-year-old charged with killing his toddler brother should be prosecuted as an adult, Channel 4 has learned about the troubled life of the boy and his mother, who give birth to the boy when she was only 12.

According to police documents, 2-year-old David Galarriago was beaten on March 14 by his half-brother, Cristian Fernandez. He died a few days later at a hospital. The 12-year-old was indicted Thursday on a charge of first-degree murder and was moved from juvenile detention to the Duval County jail.

While Frenandez's mother, Biannela Susana, 25, was not home at the time of the beating, she was charged with negligent manslaughter in connection with the toddler's death According to her arrest report, when Susana came home and found the toddler unconscious, she wiped him off, changed his clothes and put ice on his head, hoping it was just a concussion and the boy would wake up.

Police said she did not immediately call 911 and waited two hours before driving David to St. Luke's Hospital. Doctors told police that if she had sought immediate medical treatment, the boy might have survived.

Video:Court Document:Cristian Fernandez Indictment

According to court documents, this wasn't the first time that David was injured at the hands of Fernandez. The 2-year-old victim suffered a broken leg in January that was initially blamed on a fall from a jungle gym. Court records show that Susana later admitted to the Florida Department of Children and Families that she lied to investigators and that Fernandez broke his younger brother's leg while wrestling with the boy.

Police said Susana continued to allow Fernandez to baby-sit his younger brother.

While there is no precedent for charging a 12-year-old with first-degree murder in Duval County, State Attorney Angela Corey said that her office had no choice.

"We were not comfortable, based on his history and the events where he killed his 2-year-old brother, that we could protect anyone that he was around," Corey said. "The juvenile system does not give us sufficient options or enough time. Basically, we would have lost jurisdiction over him in about 8½ years."

Fernadez's public defender disagrees, saying Fernandez should be given a chance for treatment in the juvenile system. Attorney Rob Mason said the boy has been abused his entire life and he has never been to counseling, and he stands a better chance of rehabilitation in the juvenile system than in an adult prison.

"He is motivated for treatment. He has insight," Mason told Channel 4's Jim Piggott. "He knows he needs help and he desperately wants help, and I don't think he can get the help in the state prison system."

Mason said Fernandez was found naked and dirty wandering in a hotel parking lot when he was 2 years old. Since his guardian was arrested on charges of neglect and possession of drugs and his mother was only 14, both Fernandez and Susana were placed in foster care.

As Fernandez got older, neglect turned into abuse.

"There is confirmed sexual abuse. There is confirmed physical abuse," Mason said. "It also looks from the testing been done that the sexual abuse was more extensive than what was confirmed, because they are showing some sexual acting out at a very young age."

Mason said Fernandez has never had any contact with his natural father, but his stepfather abused him.

"The stepfather had struck Cristian, caused damage to his eye. The school got involved. The police got involved, and the police were coming to the stepfather's residence to arrest him, and that is when the stepfather ended his life by gun in front of the other siblings," Mason said.

After that suicide, Susana moved the family to Jacksonville.

Though violent behavior is typical of abuse victims, prosecutors said it is not an excuse for criminal behavior.

"A lot of the people we see in the criminal justice system have rough backgrounds -- some rougher than this young man has had. We can understand, we can study it, we can look at it. We can't use it as an excuse," Corey said. "The fact and circumstances of his background are serious in and of themselves. His interaction with this baby that he killed as well as his other siblings gives us even greater concern. All of that combined was a synergy of events that we said, We have to put this child in adult court.'"

Fernandez was being held without bond. While he is in the adult jail, he is housed with other juveniles and was given access to a counselor. Susana is being housed in another part of the jail being held on $1 million bond.

Before Thursday's indictment, the youngest person to be indicted in Duval County was a 13-year-old who killed a correctional officer decades ago.