Two years after the shocking killing of 18-year-old Nia Wilson in Oakland, her killer, John Lee Cowell, has been sentenced to life in prison without the possibility of parole.

According to the San Francisco Chronicle, Cowell received the verdict in a virtual hearing on Friday.

Judge Allan Hymer handed down the sentence. Prior to sentencing, Hymer heard statements from Wilson's family, including her two sisters who were with her at the BART station when Cowell fatally stabbed her on July 22, 2018.

The Alameda County district attorney released a statement following the sentencing, ABC7 reported.

"The horrific killing of Nia Wilson and the assault on her sister will haunt her family, loved ones and our community forever," the statement read. "Mr. Cowell will now serve the remainder of his life in prison. It is my hope that Nia's family feels that justice was served and can continue on the path of healing."

Wilson's sister, Tashiya Wilson, said she was hoping for Cowell to get the death penalty, but she also wants him to suffer, CBS San Francisco reported.

“I did want death penalty for him, but he wouldn’t suffer enough as we do,” Tashiya said. “We suffer through this literally every day that we wake up, go to sleep at night.”

Nia's other sister, Letifah Wilson, was also stabbed on the train and recovered from her injuries.

“I can't forgive you for that,” the grieving sister said. 

Wilson’s mother, Alicia Grayson, said Cowell “better pray to God that he can sleep every night and go on living.”

Cowell's attorneys were hoping to prove that their client isn't mentally stable, as Blavity previously reported.

“I believe my client is incompetent, has always been incompetent and I believe he is still incompetent,” Christina Moore told the court.

But the judge rejected Cowell's attempt to prove himself as incompetent in a March 16 ruling. A few days prior, the jury determined that the 29-year-old was guilty of first-degree murder and guilty of attempted murder for stabbing Letifah.

BART surveillance cameras showed Cowell pulling a knife out of his pants and following the sisters onto a train before attacking them when they exited the station.

Although he was diagnosed with schizophrenia, prosecutors said Cowell’s actions after the murder proved that he wasn't experiencing a delusional breakdown. Prosecutor Butch Ford described the man's behavior as "goal-oriented," noting how he was seen running from the scene, dumping evidence and changing clothes. 

“He knew what he did was wrong, and he did everything he could to get away with it,” Ford said in the March trial.

In his earlier testaments, Cowell said he believed the sisters were aliens and part of a gang that had kidnapped his grandmother.

“I stabbed both of the females in the crew because I believed they would not give my grandmother back,” he said at a hearing in an Alameda County court.

According to CBS SF, Ford said Cowell, who is white, may have been racially motivated to attack the Black sisters. The prosecutor said Cowell made racial references during his testimony, saying that a Black woman punched him in the face a week before the stabbing.

Cowell also said he tried to fight the same Black woman when he saw her on a bus shortly after the fatal attack on Wilson, Ford told the court.  

Jocelyn Gama, Nia’s childhood friend, said Cowell was trying to weaponize his white privilege with the claims of mental incompetence, as Blavity previously reported. 

“I’m tired of always white individuals coming into spaces and using mental health as a card to get away with situations like this,” Gama told reporters earlier this year. “I’m tired of hearing on the news that a white man has killed a Black individual and, what they always have to say is, 'oh it’s mental illness.'”

The family of the slain sister said they're still struggling in the wake of their loved one's killing.

“July used to be my favorite month cause I knew it was my birthday month," Tashiya said. "And I knew every year that Nia was with me on my birthday. And I’m glad she was with me on my 21st.  But it’s a tragedy that I lost her three days after my birthday.  And I can’t even get excited about it anymore.”

Letifah said the attack remains a fresh memory, two years later.

"It still seems like yesterday and it’s hard to even talk about it sometimes without getting choked up,” the sister said. 

But the family is finding solace in the court's ruling.

“There’s peace that he’s not going to walk free anymore,” Tashiya said.