A 12-year-old boy, Cristian Fernandez, could be locked away in prison, if he is convicted of killing his 2-year-old half-brother.

Fernandez, who is from Jacksonville, Florida, is charged with beating his younger brother David Galarriago to death at their home in March.

Galarriago died from bleeding on the brain because of a fractured skull two days after beating. According to an autopsy, the injuries were consistent with being punched in the head.

According to court documents, Fernandez had previously assaulted his brother and broken his leg in January.

Fernandez will be charged as an adult as the prosecutor claims he is dangerous to the society. We have to protect the public from this young man, prosecutor Angela Corey said.

Fernandez may be the youngest prisoner in the United States. Corey said it's a stunning event in America's judicial history. If he is sentenced in his juvenile, he would be free when he is 21.

Fernandez’s mother, 25-year-old Biannela Susana was also accused of negligent homicide. Although Fernandez had attacked Galarriago earlier, she still let him take care of his brother.

After Fernandez had beaten Galarriago in March, Susana returned home and found the toddler unconscious. Instead of immediately calling an ambulance, she just wiped his blood, changed his clothes, put ice on his head and waited for him to wake up. It was only after two hours that she took Galarriago to the hospital. Doctors told the police that if she had brought Galarriago on time, her son would still be alive.

However, one of Fernandez's defense lawyers, Rob Mason said Fernandez is innocent as he had been raised in a broken family. His father was in jail because of sexually assaulting his mother, who was pregnant with him when she was only 12 years old.

Fernandez and his mother were placed in foster care together after he was found wandering alone outside a Florida motel as a toddler.

After Fernandez's stepfather committed suicide in presence of the family, they moved to Jacksonville, Florida in October.

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

This case has drawn the attention of many legal experts. Robert Batey, a professor from the Stetson University College of Law, said proving intent is very important.

Especially if it's a beating death, you could argue that the child did not have the intent to kill, which would be necessary even for second-degree murder. Or that the child was not capable of the cool thinking beforehand that's implied by the notion of premeditation, Batey said.