The Tennessee Supreme court has issued a ruling in the case of Cyntoia Brown, who was only 16 years old when she killed a man who solicited her for sex.

The five-justice court unanimously decided defendants like Brown, who are convicted of first-degree murder and receive a life sentence after July 1, 1995, are not eligible for release until they serve at least five decades behind bars. Due to Thursday's ruling, Brown is required to serve a minimum of 51 years in prison, according to CNN.

Brown is serving a life sentence for the murder of 43-year-old real estate agent Johnny Mitchell Allen. The incident occurred in 2004, when Allen took Brown to his home for sex. The defendant claimed she shot the victim because she feared he would kill her. 

Prosecutors argue Brown killed Allen to rob him, as she allegedly took his wallet and firearms after the fatal shooting. 

More and more details about Brown's tragic upbringing have come to light since her conviction. A PBS documentary titled Me Facing Life: Cyntoia's Story provides a closer look at the circumstances Brown allegedly endured, including emotional and sexual abuse.

In recent years, celebrities have attempted to raise awareness about Brown's case. Stars like Rihanna, Cara Delevingne, LeBron James, Snoop Dogg, and Kim Kardashian have called for her release.

Brown's case is still pending judgment in the 6th Circuit Court of Appeals.