Outrage as 13-year-old US boy faces life for murder

Caliel said the state is seeking a hybrid sentence in which Fernandez is incarcerated in a juvenile setting for the duration of the jail term, until age 21, followed up with court supervised rehabilitation.

"He will not be sent off to an adult prison, and by law he cannot," he said.

Caliel said he is hoping to reach a plea bargain before the trial and that even if the case goes to trial prosecutors would preempt a possible life sentence by the proposed hybrid sentence.

But former state attorney Harry Shorstein has also voiced opposition to the move to try Fernandez as an adult.

"I think it illustrates a lack of understanding of the adolescent brain and its development," he said. "It's totally different from an adult and yet to be fully developed."