OAKLAND  (AP) — A 16-year-old Northern California boy is being charged as an adult with hate crimes after authorities say he set another teenage boy wearing a skirt on fire on a public bus because of homophobia, authorities said Thursday.

Alameda County prosecutors charged Richard Thomas, of Oakland, with felony assault and aggravated mayhem with hate crime enhancements in Monday's attack on Luke "Sasha" Fleischman, who is hospitalized with second- and third-degree burns.

"Richard Thomas' violent and senseless criminal conduct resulted in severe and traumatic injuries to a young and entirely innocent victim," District Attorney Nancy O'Malley said after charges were filed. "The intentional and callous nature of the crime is shocking and will not be tolerated in our community."

Thomas, who had no lawyer present with him, didn't enter a plea during his arraignment Thursday. He was being held without bail and is due back in court Nov. 12. His family could not be reached for comment.

The Associated Press is naming Thomas even though he is a minor because of the seriousness of the alleged crime.

The junior at Oakland High School was arrested at school Tuesday afternoon after surveillance video from the bus helped police identify him as the suspected attacker.

Authorities say Thomas used a lighter to set Fleischman's kilt-like skirt on fire while Fleischman was asleep on an AC Transit bus in Oakland, authorities said. Other passengers came to the 18-year-old's aid after he tried to put out the flames himself.

During an interview with police, Thomas said "he did it because he was homophobic," Oakland police Officer Anwawn Jones wrote in a court affidavit.

Fleischman's mother and friends have said he identifies as "nonbinary," a designation sometimes adopted by those who see themselves as neither male or female.

Fleischman, of Oakland, is a senior at a private high school in Berkeley. He remained in stable condition at a hospital in San Francisco, and his mother said he will require massive skin grafting.

Fleischman's relatives set up a fundraising page for him Tuesday on Fundly.com, with the hope of raising $20,000 in 10 days to go toward his medical bills. The site said Luke Fleischman requires "several surgeries."

The goal was surpassed 24 hour later as more than 400 supporters donated more than $21,000.