Cinque Henderson, a new teacher, knew he needed help. His seventh-grade English students were far behind in vocabulary and much else. But, to his shock, the principal he had counted on for support instead walked to the front of his class within two months of his arrival and denounced him to his students.

Henderson had been experimenting with having every student in his Los Angeles Unified School District class copy out the definitions of two words at the beginning of each class. It seemed to improve their comprehension, but when the principal visited with two district officials, she was enraged.

“Young people, tell me you aren’t doing this,” the principal said, according to Henderson. “Tell me you aren’t simply copying vocabulary definitions.” Henderson tried to explain, but she cut him off. “I’m not speaking to you,” she said.

“Young people,” she said, “if this is all your teacher does, he has failed you.”

Principals bullying staff is an old problem about which there is little research. All signs indicate it still hurts many schools , though some areas are more prone to it than others. That this administrator’s supervisors tolerated such behavior suggests Los Angeles’s reputation for mistreating teachers is not going away any time soon.

Asked to respond to Henderson’s account, school district spokeswoman Shannon Haber said: “I have no information to share.”

Henderson is a writer who has contributed to the New Yorker, the New Republic and the HBO show “The Newsroom” and wanted to help low-income children. The principal of low-performing Audubon Middle School hired him at age 38 apparently because of his good work as a substitute. Fifty-nine percent of Audubon students are black, as is Henderson, another mark in his favor.

But he had trouble keeping order. His mentor teacher wasn’t much help, he said. The principal seemed to resent his suggestions and avoided his attempts to speak to her until her verbal attack in early October 2014.

A few days later, Henderson said, the principal spent 90 minutes lecturing him on what she called the 11 pages of mistakes he had made, which she said she would give him in writing but never did. She said his teaching was arrogant and self-centered. She said she knew he had gone to Harvard, but “I have six degrees, so what?” She said the students’ desks were poorly arranged and his classroom management was abysmal.

Then she took the humiliation to a level I have never heard of in a U.S. school: Henderson said she marched him into seven other classrooms and “insisted that I say out loud what these teachers were doing that were better than I was doing.”

She berated other teachers, but he was a favorite target, he said. He tried to improve. He invented a contest called “Stump the Scholar,” a student favorite, in which they used their notes to answer questions. He had Oscar-nominated director Orlando von Einsiedel speak to his class. His students published a six-page newsletter, the first in the school in many years.

It didn’t help his case. He was told the principal felt he was stealing her ideas. In April she ordered his dismissal. The assistant principal suggested he resign, but that would have threatened his teacher’s license. Instead he filed a 50-page workplace violence complaint accusing her of bullying.

He said the investigator told him he had a case if it could be proven. But only one of his nine witnesses was questioned, he said. His complaint was denied due to insufficient evidence.

Two other teachers confirmed Henderson’s account. One described a “palpable sense that all of us working here may be dispatched at any moment.” Another called the principal “a very vindictive person.”

Back with his writing career, Henderson still wonders why a principal would turn so quickly, publicly and viciously against him.

I wonder the same thing. Also, why is that principal still in charge of a school full of teachers who need all the support they can get?