OKLAHOMA CITY - Thursday, the court of criminal appeals said Oklahoma's law that says 15, 16 and 17 year olds charged with first-degree murder can be charged as adults, is constitutional.

The court made the ruling after a Thursday morning hearing in the case of Broken Arrow teenager Michael Bever, who's charged with killing his family last summer.

The ruling means he will be tried as an adult. His attorney argued the law was unconstitutional and Bever should be tried as a juvenile.

Robert Nigh, the attorney for the 17 year old, argued the law is unconstitutional because if Michael Bever is convicted, he's going to go to prison for the rest of his life and will essentially die there.

Nigh says that is the same as the death penalty, which the U.S. Supreme Court has said is unconstitutional to assign to a juvenile.

But the district attorney argued the legislature knew exactly what it was doing when it decided teenagers who commit very adult-like crimes should face adult-like consequences.

Nigh argued teenagers' brains are not fully developed like adults so they shouldn't be given adult punishment. He said if you send a teenager to prison for the rest of his life, it's basically the same thing as a death sentence.

"It's not a death penalty,” Tulsa County District Attorney Steve Kunzweiler said. “We know right now Michael Bever is an adult, and the crimes were committed when he was almost 17, and the Supreme Court held the death penalty is not available.”

Nigh argued that if a child was physically and emotionally abused, and virtually kept prisoner in his home his entire life he should be given a chance at rehabilitation, not prison since that abuse kept him from knowing right from wrong or the value of life.

The DA said he hasn't seen any facts to back up claims that the Bever children were mistreated.

"Certainly, I would suggest I have not heard that from the surviving member of the family," Kunzweiler said.

That survivor, a sister, is expected to testify that Michael and their older brother Robert, 19, stabbed their parents and three siblings to death.

Both Michael and Robert have pleaded not guilty to five counts of first-degree murder.

The next step is a preliminary hearing next month where the DA will present evidence, and a judge will decide if there's enough evidence to make the Bever brothers stand trial.