The Santa Fe killer will not face the death penalty and could be paroled. Here's why.

The 17-year-old Texas student accused of walking into Santa Fe High School Friday morning to murder his classmates will not face the death penalty and could be paroled in the future.

What are the details?

The suspected killer, who TheBlaze will not name, is considered an "adult" in the Texas criminal justice system. But his state classification, and the fact he is charged with capital murder, will not stop a 2005 Supreme Court ruling from keeping him alive.

The high court ruled in Roper v. Simmons that imposing the death penalty on persons younger than 18 years old is a violation of the U.S. Constitution's Eighth Amendment, which outlaws "cruel and unusual punishment." The landmark decision came just three years after the Supreme Court outlawed the death penalty for people deemed intellectually disabled.

In addition, a 2012 Supreme Court Case — Miller v. Alabama — determined it is unconstitutional to sentence juvenile offenders to life in prison without the possibility of parole no matter how serious of a crime the juvenile committed.

Supreme Court Justice Elena Kagan wrote in the majority opinion that sentencing a juvenile to life without parole also violated the Eighth Amendment. As USA Today noted, that means the suspected Santa Fe killer could be eligible for parole in 40 years, or when he is 57 years old.

Why did SCOTUS rule the way it did?

Michael Radelet, a sociology professor at the University of Colorado at Boulder, told USA Today the court's rulings had nothing to do with depravity of crimes, but rather the cognitive development of minors.

"The courts ruled based on the idea that those 17 and younger don’t have the cognitive development to appreciate right from wrong. Cases like this that are especially violent and an enigma make some people think they are more deserving of death, but the ruling is about the development of the juvenile brain," Radelet told USA Today.

However, Radelet expressed caution to those who believe the suspected Santa Fe killer will not face adequate justice because he is ineligible for the death penalty and life without parole.

"It’s wrong to say this young man can’t be held responsible for these crimes," Radelet said. "Forty years is a tough row to hoe, and even then a parole board might not agree he’s not totally damaged or able to make a satisfactory transition into the community in 2058."