SAN FRANCISCO (AP) Police on Tuesday were investigating the physical and sexual assault of a transgender teen who said he was attacked in a bathroom at a suburban San Francisco public school where another transgender student had reported being the target of bullying.

The 15-year-old student assaulted Monday, who is biologically female but identifies as male, told officers he was leaving a boy’s bathroom at Hercules Middle/High School when three teenage boys pushed him inside a large stall and assailed him, Hercules police Detective Connie Van Putten said.

Van Putten said the attackers reportedly made disparaging remarks to the student, allowing police to treat the case as a hate crime.

“He walked himself to the health center, and was obviously very upset when he talked to officers,” Van Putten said. “He is doing as well as can be expected under the circumstances.”

It was the first assault of a transgender student made public since a new California law went into effect on Jan. 1 guaranteeing students the right to use the bathrooms and locker rooms that match the gender with which they identify.

But even before the law took effect, the West Contra Costa Unified School District, which includes Hercules Middle/High, gave transgender students their choice of which school facilities to use, district spokesman Marin Trujillo said.

Trujillo would not say how long the assaulted student had been using the boy’s restroom but stressed that it would have been permitted even if the law had not been passed.

“We have transgender students at our elementary, middle and high schools and have been making these types of accommodations for many years already,” he said.

Opponents of the new law recently tried to repeal it at the ballot box but failed to gather enough signatures to qualify a referendum for the November election. School officials suspect the campaign may have indirectly played a role in Monday’s attack by fueling fears among parents and students, Trujillo said.

“We believe as a district, and the superintendent does, that the latest efforts by the petitioners to bring down the law has stirred up a lot of hate and it is showing up in the wrong places,” he said.

The teen attacked Monday was taken to a hospital for treatment and released to his parents. No suspects have been identified and detectives on Tuesday were interviewing students on the campus of 1,800 students in grades 6-12 about 20 miles northeast of San Francisco.

Last fall, another transgender student went public with an account of what life was life for her at Hercules High after she got into a fight with three other girls that was caught on a cellphone video that went viral. The transgender teenager, Jewlyes Gutierrez, a biological male who identifies as a female, said she had repeatedly complained about being harassed at school before the brawl.

No one was seriously injured in the fight, but Gutierrez, 16, was charged with misdemeanor battery. Civil rights groups and the president of the school board have called on prosecutors to drop the charge after questioning why she was the only one to face a possible criminal penalty.

Carolyn Laub, executive director of the Gay-Straight Alliance Network, which supports and trains student organizations that serve gay, lesbian, bisexual and transgender students, said Monday’s attack indicates that Hercules High has serious safety problems that have nothing to do with the new law.

“This is a horrible incident with a young person who has been sexually assaulted. It’s not about bathrooms,” Laub said. “It’s an attack and it happened at a school where violence has been rampant and allowed to escalate to where something like this has been allowed to occur.”

Trujillo said it was wrong to put Gutierrez’ experience and Monday’s assault in the same category and denied that the school has unusual behavior problems.

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