Boy, 12, could face life in prison for murder

He allegedly killed his brother, two, and prosecutors fear he is so dangerous they want to lock him up for the rest of his life - and he's only 12-years-old.

Cristian Fernandez is set to be face trial as an adult in the US and could become America's youngest person to be given a life sentence, the Daily Mail reported.

"We have to protect the public from this young man," prosecutor Angela Corey said.

She wants Fernandez to be charged as an adult.

Fernandez's two-year-old brother David Galarriago died after being hit with blunt force trauma consistent with punches to the head, according to an autopsy.

He spent two days in hospital with a fractured skull that caused bleeding in the brain before he died.

According to a police report, Fernandez's mother found the toddler unconscious and bleeding, but waited two hours before calling for an ambulance hoping it was just concussion.

The boy may have survived if he had been treated immediately, doctors said.

Fernandez is accused of beating his brother to death in their Jacksonville, Florida home in March.

It has been reported Fernandez had broken his brother's leg in the past.

Prosecutors believe they had to step in now before the boy caused more damage after they reviewed his behavioural history.

"It's one where you go, at what point do you step in, so you prevent another murder, and that's how we felt in this case," Corey said.

"If we don't intervene now and do the tough thing. We have to protect the public from this young man.

"The fact that we indicted a 12-year-old in and of itself is a stunning event and a sad event in our prosecutorial lives that we had to do this, but it is the only legal mechanism that we can use to protect the community from this particular defendant at this point."

According to Fernandez's defence, he had gone through family turmoil, sexual battery and an abusive stepfather's suicide.

Fernandez's mother, Biannela Susana, 25, is also being charged with negligent homicide in David's death.

Susana was just 12-years-old when she had Fernandez, and both were put into the state foster care system two years later.

Documentation told of a life of abuse and the two were living with Fernandez's grandmother, who had a drug habit, prior to foster care.

He also had to deal with the trauma of his stepfather shooting himself in front of the family after police came to arrest him on child abuse charges.

After being assessed by two forensic psychologists, Fernandez was found to be emotionally underdeveloped but there was still hope he could be reformed despite his history.

One of his defence attorneys, Rob Mason, said the boy's father had not been around much, partly because he was in prison shortly after getting Fernandez's mother pregnant.

"The whole system has failed him. This child clearly is a victim. We think he can be rehabilitated and, as his lawyers, we will fight for that," Mason said.