SAN JOSE — Eagerly anticipating her English students delving into “Harry Potter and the Sorcerer’s Stone,” Maimona Afzal Berta arrived early to school Sept. 11. Her classroom walls at Fischer Middle School depicted a London skyline; soon the room would also include the famous Platform 9¾, a Hogwarts sorting hat and hanging replicas of floating candles.

But when she walked in she was stunned by a hateful reality. Anti-Muslim slurs and obscenities were scrawled on her classroom’s windows and door. Spray-painted graffiti also defaced other rooms and rooftop air-conditioning units at the San Jose campus.

“It was devastating,” the special-education teacher said. “I felt completely targeted, and not even safe in a place I consider home.”

The latest attack came after Fischer recorded multiple instances of harassment, with students making derogatory comments and threatening gestures during the spring semester at Berta, a classroom aide and an after-school supervisor, all women who wear a hijab, the Muslim head scarf. Berta — who has counted 15 incidents beginning in January — has filed a grievance and a formal complaint with the Alum Rock Union School District.

Berta’s experience reflects the rising backlash against Muslims with schools mirroring what’s happening around the country, educators say. The FBI reported crimes against Muslims rose 67 percent in 2015, and 27 percent in 2016. Among the Southern Poverty Law Center’s tally of reported harassment and intimidation in the first 10 days of the Trump administration, 37 percent were reported at K-12 or university campuses. Berta has taught for five years, but this is the first year she has encountered any sort of harassment, she said.

With a president quick to deride critics and blame Muslims and immigrants, the White House example “creates a lot of chaos that is unnecessary,” said Fischer Principal Imee Almazan, “when you have a leader of country who is saying what he is saying.”

The unceasing bullying at Fischer in East San Jose also reflects the challenge facing campuses, even those run by well-meaning adults. The school’s walls feature images and quotes from a panoply of civil-rights leaders, from Filipino founders of the United Farm Workers Union, to Pakistani girls’ advocate Malala Yousafzai and author and activist Maya Angelou.

So far, several students have been disciplined with suspensions from lunch or school and one has been transferred to another school. But authorities haven’t identified any graffiti suspects. Fischer does not have surveillance cameras.

“At the Alum Rock Union School District, we will never tolerate any behavior that makes either our students or team members feel marginalized,” Superintendent Hilaria Bauer wrote Monday in a statement. She and other officials have expressed sympathy for Berta and outrage at the harassment. Administrators have spent hours investigating, counseling and discussing standards of behavior in response to the incidents.

Yet Berta, who grew up in East San Jose, now feels so insecure that her husband, also a Fischer teacher, escorts her to class every morning.

Students have kicked her classroom door and yelled “shoot her,” labeled her a terrorist, accused her of working with ISIS and shouted to others that she was going to “kill us all.”

Almazan said that two other victims, who no longer work at Fischer, confirmed they also had been bullied but had not reported it at the time. They could not be reached for comment.

In response, Fischer has held assemblies on bullying, workshops on stereotypes and misconceptions about Muslims, and exercises in character-building. The school plans to train teachers Tuesday in an interactive curriculum offered by the Islamic Network Group.

Berta, however, wants more timely and effective responses. She was incensed that after an Oct. 2 incident — when she heard banging on her door and windows and someone yelled “shoot her” — one student was given lunch detention, then 10 days later suspended for two days. The incident was reported to police and the vice principal spent more than a day investigating, Almazan said.

“Students will get lunch detention for wearing colored shirts or not wearing their lanyard,” said the 23-year-old Berta, who graduated from college at 18. “To put saying ‘shoot her’ in the same category as a dress code violation didn’t make any sense to me.”

As for the delay in dealing with harassers, Almazan said investigation takes time. After the spring incidents the staff decided to craft some lesson plans to promote tolerance, but had to hold off because of state testing. In October, some response lagged because top Alum Rock district administrators were attending a labor-negotiations training in Massachusetts.

But delayed response is not considered the best practice in dealing with bullying.

“If a kid doesn’t get pulled out immediately for egregious behavior, word gets out fast,” said Randy Barber, a Fischer music teacher and union representative.

He blames large class sizes, up to 37 student in some cases, that allows behavior to get out of hand. “You literally don’t have a ratio of enough grownups to kids to keep a steady handle” on campus, Barber said.

Almazan said she’s been working on improving school culture. But that, she said, takes time.

Establishing a norm that doesn’t tolerate harassment is key, said Anne Ehresman, executive director of Project Cornerstone, a YMCA program that helps support students to live healthily and behave responsibly. With effective training, kids reinforce the culture and don’t remain bystanders to bullying.

This month, a student across the quad repeatedly gestured as if he were shooting a gun at Berta. In response, the district transferred him to another school and notified police, but somehow any follow-up fell through.

“I’m tired of the lip service. You can’t keep telling people that you care and want to stop hate,” Berta said, “and yet you don’t follow through with actions.”

She has turned down district offers to transfer her to another school.

“That’s not solving the problem,” she said. “I feel personally responsible so that this doesn’t happen to anyone else. No one should have to experience this. It’s been terrible to go through, the level of anxiety I get walking onto campus.”