The motion to dismiss the indictment of 13-year-old Cristian Fernandez on a murder charge was denied Tuesday by Judge Mallory Cooper.
Cooper had delayed her decision before issuing her ruling late Tuesday morning.
"With today's order, the state attorney's office will continue to move forward with the prosecution of Cristian Fernandez," the office said in a statement. "We will not comment further about the order or the pending case."
Fernandez was 12 when he was arrested in March 2011 and charged with murder in the death of his 2-year-old half brother.
"We understand Judge Cooper's ruling," defense attorney Hank Coxe said in a statement. "It will not distract us from our commitment to fight the continued prosecution of this 12-year-old child for first-degree murder as an adult, exposing him to a life in prison without parole."
Defense lawyers claimed the first-degree murder case could not proceed because Florida sentencing guidelines require anyone convicted of that crime to face either the death penalty or life in prison without parole, but the U.S. Supreme Court ruled this summer that it's unconstitutional for juvenile offenders to get mandatory life sentences.
Prosecutors said that the old Florida law that called for a 25-year-to-life sentence could apply, but defense attorneys said Fernandez should not be tried under the current law because they can't advise their client what kind of sentence he could face.
In Cooper's ruling, she said that's "a premature argument" because Fernandez has yet to be convicted of a crime. Cooper said that if Fernandez is convicted, the sentencing court would then have to consider the circumstances.
In the meantime, the case will continue as scheduled, with a hearing set for next week.
"I imagine the defense is thinking now whether to appeal this order and what the ultimate outcome of that would be," Channel 4 legal analyst Ed Birk said.
Birk reviewed the judge's order.
"If it turns out after trial that Cristian is convicted, then the issue will be what we call 'ripe for the judge's decision,'" Birk said. "If he's acquitted, then there won't be any need for the judge to decide this point of law about this sentencing statute."
Fernandez's tentative trial date in the murder case is set for March 4.
"I just picture him being in a home, not being further abused by being put through all of this and facing a trial," Fernandez supporter Alicia Torres said. "I hope he gets acquitted. I hope it doesn't even get to trial."