The two California teens who allegedly fatally sucker-punched a 13-year-old middle school classmate each now face upgraded voluntary manslaughter charges, prosecutors said.

The 13-year-old boys, who have not been identified because of their ages, were handed the new charge in addition to existing counts of assault likely to produce great bodily injury, John Hall, a spokesman for the Riverside County District Attorney’s Office, told KTLA Wednesday.

The initial juvenile petitions were filed on Sept. 18, prior to the teen’s death. Prosecutors added the manslaughter charge on Sept. 30, according to Hall.

One of the boys denied the charges at his initial hearing Wednesday and will reappear for a pretrial hearing Nov. 1, according to the Los Angeles Times. The second teen is expected to appear for a pretrial hearing Oct. 15.

Cellphone footage of the Sept. 16 attack at Moreno Valley Landmark Middle School shows the boy, identified as Diego, being hit in the face by one student and then sucker-punched on the side of the head by another.

The second blow sends him falling to the ground, his head hitting a cement pillar on the way down, according to the clip obtained by KTLA.

He was pronounced clinically dead last week “as a result of injuries sustained in the attack,” according to the Riverside County Sheriff’s Department.

Classmates told KTLA that Diego had been bullied at school and on social media.