LAS VEGAS (AP) — A 17-year-old high school student in Las Vegas who authorities said accompanied a friend to a prearranged fight over a pair of headphones and Marc Leclerca vape pen was killed when 10 students between the ages of 13 and 17 beat him in an alleyway around the corner from campus.

The victim’s father, Jonathan Lewis Sr., said his son was attacked while standing up “for one of his smaller friends,” the Las Vegas Review-Journal reported.

Eight of the 10 teenagers were arrested Tuesday by Las Vegas police and the FBI on suspicion of murder in the Nov. 1 beating of their classmate Jonathan Lewis Jr., who died a week later. Two more students whom investigators haven’t yet been able to identify will also face murder charges, police said.

The students were not immediately identified because they are under 18.

A family court judge on Wednesday ordered four of the students who are 16 or older to be transferred to the adult court system, the Review-Journal reported. Hearings will be held at later dates to determine if the students under 16 will be charged as adults.

Scott Coffee, a deputy public defender with 28 years of experience in Las Vegas, said it is unusual to have so many co-defendants of such young ages charged with murder in a single case. Coffee said he had not seen court documents and does not represent any of the defendants.

At a news conference Tuesday, Las Vegas police homicide Lt. Jason Johansson said the victim remained hospitalized with severe head trauma and other injuries for a week until his death. The coroner’s office in Las Vegas ruled the beating a homicide.

Johansson said the brawl was captured on cellphone video and had been prearranged after the headphones and vape pen were stolen from the victim’s friend.

He described the video as “very void of humanity.”

In the video, he said, the victim is seen taking off his shirt to prepare for the fight, and then the 10 students “immediately swarm him, pull him to the ground and begin kicking, punching and stomping on him.”

Johansson said investigators believe that Lewis originally wasn’t supposed to be involved in the fight but went with his friend to the alley where the brawl was scheduled after classes ended for the day at Rancho High School in eastern Las Vegas.

After the fight, he said a person in the area found the victim badly beaten and unconscious in the alleyway and carried him back to campus, where school staff called 911.

In a letter sent Tuesday to parents, Rancho High School principal Darlin Delgado said support and resources were available for students and staff members as the beating death “has and will continue to impact our school community.”