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The bullying came at school dances and in class, on Facebook and back at the dorm by girls who called themselves "Oprichniki," a Russian attack squad notorious for torturing suspected enemies of a 16th-century czar.

The cruel clique at the exclusive Miss Porter's School allegedly harassed Tatum Bass for months, until two doctors advised her to take a break. That's when her tormentors put a "For Rent" sign on her bed and one of the nation's most selective, all-girls boarding schools threatened to expel her.

Bass and her parents responded with a federal lawsuit that offers a disturbing glimpse into life on the leafy campus in the affluent Hartford suburbs. To match tuition that can cost nearly $43,000, the school has an A-list of socialites, diplomats, artists and public servants among its graduates, including Jacqueline Kennedy Onassis and Gloria Vanderbilt.

According to the lawsuit, Bass was on the honor roll, played sports and was elected by her peers to a top position in student government before her trouble began earlier this year. As activities director, she proposed holding the senior prom with other schools nearby.

Opposition to the idea ballooned, leading to bullying and taunts that Bass was "retarded" because she has attention-deficit disorder. Bass said in the suit that the girls turned on her, calling her "stupid" and peppering her with profanity and insults. She said she was bullied in front of hundreds of people at a school dance, in classes, around campus, in text messages and online on the Facebook social networking site.

"This was the first time that negative attention was drawn to her disability at (the school)," the lawsuit said. "Oprichniki members were at the forefront of taunting Tatum in class and advising others about her disability."

The lawsuit names the 165-year-old school and its headmaster, Katherine Windsor, as defendants. Windsor said in a written statement Wednesday that the lawsuit's claims "as portrayed in the media will be defended vigorously, and we believe that a comprehensive hearing of the facts will result in the exoneration of our school."

Messages left for Tatum's attorneys and family were not returned. None of Bass's tormentors are named in court papers.

In the depths of the ordeal, Bass said she uncharacteristically cheated on an art history test — then was so racked with guilt that she confessed to Windsor. Bullying intensified after she returned from a three-day suspension.

"(Her) emotional stress and anxiety became overwhelming," the suit said.

The lawsuit said the school and Windsor inflicted long-term damage on Bass's academic career by notifying at least one college about the suspension without giving her a chance to offer her side. The expulsion threat soon followed for her "unexcused absences" when she tried to complete her studies off-campus, a violation of school rules not detailed in the lawsuit.

A degree from Miss Porter's is considered a ticket into the Ivy League and a future potentially filled with wealth and privilege.

Like Bass — from Beaufort, S.C. — two-thirds of about 330 students at Miss Porter's this year are boarders from 22 states and 20 countries. The school's annual tuition is nearly $43,000 for boarding students and about $33,000 for "day students," who live within driving distance of the Farmington campus about 10 miles west of Hartford.

Now, Bass' status at the school is unclear. The lawsuit asks a judge for an injunction barring Miss Porter's from sharing her academic status with colleges to which she has applied. It also asks for unspecified damages and reinstatement in good standing so she can graduate.