Four Las Vegas teenagers pleaded guilty Tuesday to voluntary manslaughter in the fatal beating of their high school classmate, as part of a deal with prosecutors that kept them from being tried as adults.

The teens originally were charged in January as adults with second-degree murder and conspiracy in connection with the November death of 17-year-old Jonathan Lewis Jr.

The attack was captured on cellphone video and shared widely across social media.

Each teen faces incarceration at a juvenile detention center for an undetermined length of time, the Las Vegas Review-Journal reported.

Karen A. Connolly, an attorney for Damien Hernandez told CBS News, “Though not one of the major participants, Damien deeply regrets his participation in the melee which resulted in Jonathan’s tragic death. He accepts full responsibility and will accept whatever punishment is meted out.”

Minors prosecuted in the juvenile court system in Clark County, which includes Las Vegas, don’t face traditional jail or prison sentences and instead are released from custody after they complete rehabilitation programs, according to Brigid Duffy, director of the juvenile division of the Clark County district attorney’s office.

Defense lawyer Robert Draskovich, representing one of the four teens, said after court Tuesday that the deal “was a very fair resolution.”

CBS affiliate KLAS-TV reports that Draskovich said there’s no sentencing range for the teens as part of the plea agreement and it’s up to a judge to decide on the sentencing for each one

Lewis’ mother, Mellisa Ready, said she doesn’t agree with the plea deal.

Ready called the agreement disgusting and broke down in court Tuesday morning.

“There’s literally no one being held accountable with true punishment for my son’s murder,” she told the Review-Journal. “It’s disgusting.”

KLAS says Ready criticized the plea agreement before, claiming she wasn’t notified of the deal when the teens initially accepted it on Aug. 1.

“I would’ve disagreed with the deal entirely. They should be accountable as adults – they made an adult choice,” she said. “They knew that when they were stomping on my child’s head that he was going to die as a result.”  

In a statement to The Associated Press after terms of the deal were made public, District Attorney Steve Wolfson’s office defended the resolution of the case as thoughtfully addressing both the egregious facts and potential legal challenges that prosecutors would have faced at trial.

The statement said the juvenile court system also is better equipped to offer the young defendants resources for rehabilitation.

In Nevada, a teenager facing a murder charge can be charged as an adult if they were 13 or older when the crime occurred.

Authorities have said the students agreed to meet in an alleyway near Rancho High School to fight over a vape pen and wireless headphones that had been stolen from Lewis’ friend. Lewis died from his injuries six days later.

A homicide detective who investigated the case told the grand jury that cellphone and surveillance video showed Lewis taking off his sweatshirt and throwing a punch at one of the students, according to court transcripts made public in January. The suspects then pulled Lewis to the ground and began punching, kicking and stomping on him, the detective said.

A student and a resident in the area carried Lewis, who was badly beaten and unconscious, back to campus after the fight, according to the transcripts. School staff called 911 and tried to help him.