Los Angeles (CNN) The nation's second largest school district has been hit with a $1 billion class-action lawsuit alleging it conducts "witch hunts" against older teachers in a "shrewd" effort to save money on retirement benefits.

The suit was filed Thursday on behalf of about 2,000 teachers by Rafe Esquith, 61, one of the Los Angeles Unified School District's best-known and most popular teachers.

It comes on the heels of reports that the L.A. school board voted unanimously and behind closed doors to fire Esquith for misconduct. Earlier this year, Esquith was pulled from his classroom and placed under investigation.

Esquith's case gained the support of actors Hal Holbrook and Sir Ian McKellan, longtime fans of the teacher's efforts to bring classic works by Mark Twain and William Shakespeare to low-income immigrant students.

Thursday's lawsuit "is the largest class action by teachers in the history of public education," said attorney Ben Meiselas, who represents Esquith, the lead plaintiff, along with attorney and CNN legal analyst Mark Geragos.

The school district declined comment. Spokeswomen said district officials hadn't reviewed the lawsuit and couldn't comment on the firing because it is a confidential personnel matter. One spokeswoman pointed to a report about the firing , quoting anonymous district sources, in Thursday's Los Angeles Times. That report said the board acted on the recommendation of senior administrators.

Esquith's suit accuses administrators of abusing disciplinary measures to push out older teachers so the district doesn't have to pay them retirement benefits, including pensions and health care.

It alleges Esquith's treatment fits a pattern: that teachers nearing retirement age are abruptly removed from their classrooms and placed in what teachers and their union refer to as "teacher jail" -- essentially spending time in an administrative office or at home awaiting the outcome of investigations that often lead to firings.

District officials could not say how many teachers had been sent to "teacher jail" over the past five years. But the district's attorney, David Holmquist, recently said about 170 of the district's 31,748 teachers are currently under suspension for suspected misconduct. If the past is any indicator, fewer than half of them will return to the classroom, he added.

Geragos told reporters at a news conference that more than 1,000 teachers have sent emails saying they, too, had been subjected to teacher jail. And, he said, Esquith's former students have complained about how they've been questioned by the district's investigators.

Geragos said the district employs "an investigative hit squad that goes out and intimidates and tries to extract statements from students that they then can use for kangaroo court-type proceedings."

"I'm calling for the complete shutdown of LAUSD," Geragos said. He described the district as "a corrupt organization" that has smeared Esquith's reputation through "scurrilous and scandalous leaks."

Thursday's suit seeks to grant Esquith legal status as a "whistleblower" and follows months of failed negotiations and heated rhetoric over his case.

Until April, Esquith taught fifth grade at Hobart Boulevard Elementary School. He spent 30 years at the school, which is in a neighborhood of low-income families and first-generation immigrants.

Esquith also led a well-known theater group, the Hobart Shakespeareans, which put on annual musicals based on plays by William Shakespeare. The productions, as well as several best-selling books Esquith has written about his teaching philosophy and methods, brought him international acclaim as an educator.

Rafe Esquith, second from right, was among those presented with a National Medal of the Arts by President George W. Bush in 2003.

Among Esquith's accolades: a 2003 National Medal of the Arts. a Walt Disney American Teacher Award as Oustanding Teacher of the Year. a Parents Magazine "As You Grow" award. and an Oprah Winfrey $100,000 "Use Your Life" award.

He's also been made an honorary member of the Order of the British Empire.

Esquith and the Hobart Shakespeareans gained widespread renown several years ago after PBS aired a documentary about them. In 2012 they were featured at the annual TED Conference.

Earlier this year, Holbrook and McKellan appeared in a video on YouTube in support of Esquith.

"A remarkable teacher," Holbrook calls him.

"Rafe Esquith is my hero," says McKellan.

Lawsuit alleges 'consistent pattern'

Esquith's lawyers said they have not received notice of his termination, and details of the misconduct that led to the decision to fire Esquith were not given.

But the district has laid out some of the allegations in past communication, including correspondence with Esquith, his lawyers and the board of the Hobart Shakespeareans, as well as a statement issued by the superintendent earlier in the investigation. Those allegations include:

• Talking about nudity in class

• Keeping sexual material on his school computer

• Buying food for students without parental permission

• Failing to obtain proper permission slips for field trips

• Mishandling money from the Hobart Shakespearans' nonprofit organization

• Vague "government ethics" violations

• Physically abusing a boy at a Jewish Day camp more than 40 years ago, a decade before Esquith began teaching

Investigators also at one point demanded 15 years worth of personal tax returns, bank records and receipts in connection with the Hobart Shakespeareans.

Esquith says that while he is not perfect, he is innocent of sexual or financial wrongdoing. He says he personally paid for The Hobart Shakespeareans' productions and travel costs, including college visits and an annual trip to the Oregon Shakespeare Festival.

Esquith can appeal the firing before an administrative judge. He previously filed a defamation suit seeking reinstatement. But filing the class action lawsuit signals he is taking a different course. The suit seeks punitive damages, but it does not demand reinstatement.

It does seek a court order shuttering the "teacher jails" and damages "in excess of $1 billion" on behalf of approximately 2,000 Los Angeles teachers. It asks the court to grant teachers the same due process rights they'd have if they were facing criminal charges. -- the ability to know the nature of the charges and challenge their accusers.

Instead, according to the lawsuit, the district's investigations of its teachers are vague, open-ended and meandering "witch hunts" to dredge up dirt and justify firings.

The investigations and firings "follow a remarkably consistent pattern," the lawsuit states. "An older, experienced, and well-paid teacher will unexpectedly be pulled from the classroom in dramatic fashion." They are then told to either report to an adminstrative office, or two phone in twice a day from home.

Teachers are never informed why this is happening, or given details about the alleged misconduct, according to the suit.

"LAUSD provides no description of any pending complaint or charges against the teacher whatsoever," the suit says. "Disturbingly, from the very outset, LAUSD administrators label the teachers as immoral, unethical, thieves, abusers or criminals, while at the same time the LAUSD places the teachers under a gag order."

They are left to sit in a cubicle, "staring at the wall" for six hours a day. Some of the "inmates" in teacher jail have been there for three years, the suit states. They describe the experience as degrading, a cruel form of torture for someone used to leading a classroom.

'A bump in the road'

Esquith says his journey to teacher jail began on March 19 -- with a joke. The class had read the Mark Twain classic, "The Adventures of Huckleberry Finn" together. There was little doubt they'd all be on the same page.

He brought up the subject of money. Or rather, the lack of it. If they didn't raise more, they'd have to perform like the king in Huck Finn.

Naked.

Students nodded as he quoted the passage:

"At last, when he had built up everyone's expectations high enough, he rolled up the curtain. The next minute, the king came out on all fours, naked. He was painted in rings and strips all over in all sorts of colors and looked splendid as a rainbow."

Another staffer overhead. She complained to the principal that Esquith was talking about nudity with fifth graders.

He was summoned to the office, where the staffer was sitting, crying. "I don't want this to ruin our friendship," she said. Seeing his puzzled expression, the principal tried to smooth things over, telling Esquith he had nothing to worry about.

"This is a bump in the road," Esquith said the principal told him. "I need to counsel you that you need to be careful what you say in front of students."

When he returned from spring break, Esquith was told the staffer had lodged a formal complaint, which had been forwarded to the state teacher credentialing committee in Sacramento.

"This is about nothing," Esquith said the principal told him.

School district officials pushed for Esquith to write an apology. He chose his words carefully:

"I am deeply and sincerely sorry that any comment someone heard, or thought they heard, has anyone uncomfortable. I am a teacher who prides myself on professionalism. I dress immaculately for the job. Over a thousand teachers a year come to my class to seek my guidance on the profession of teaching. As a proud teacher, I am deeply saddened by this situation."

The apology apparently wasn't enough. On April 10, Esquith was informed he was being taken out of his classroom because of allegations of serious misconduct. He was told to report to teacher jail. He was ordered to speak to no one; if he talked, he'd lose his job immediately.

Other teachers around him gossiped or worked on lesson plans, he said. Esquith kept to himself and tried to figure out what was happening.

While he was in teacher jail, the staffer who had filed the formal complaint began sending him supportive emails:

"I just want you to know I am here for you, and if there is anything you need please let me know!" said one, sent on April 22. "My thoughts are with you constantly and I wish you the best."

According to the suit, Esquith was not given a chance to defend himself. The one meeting he had with school officials took on a distinctly accusatory tone. At the meeting, on May 27, he said investigators asked him, "What teachers don't like you? Who did you date in college?" The questions struck him as bizarre.

He asked school officials why they didn't want to know who liked him, pointing out that his classroom is a magnet for teachers from around the world. "That's not our job," he said he was told. "Our job is to find the people who don't like you."

Esquith recalled with a rueful smile what he was told by the investigator who vetted him for Oprah Winfrey: "You lead a very boring life."

Eventually, the district's investigators started pulling his former students out of class and knocking on their doors at home. Again, the questions seemed loaded.

"This fits a disturbingly consistent pattern and practice of LAUSD investigators terrorizing, tormenting and abusing students in order to extract statements that fit into their narrative to terminate a targeted teacher," the lawsuit states.

According to the suit, students were asked questions like: "What creepy things did teacher X do?" or "Has teacher Y ever looked at you funny?" Investigators also asked if their teacher "made them feel uncomfortable" or to explain why a certain teacher might be "racist."

Many of Esquith's former students and his supporters say they have difficulty reconciling the questions with the dedicated teacher they know.

Half a dozen former students who spoke with CNN said they never experienced anything inappropriate with their teacher. Some said they consider him a mentor and a member of the family.