CHICAGO (CBS) — A special education teacher who has been a vocal detractor of the policies at Chicago Public Schools has accused the district of going on a “witch hunt” after she was suspended and told CPS is moving to fire her.

CPS officials have confirmed the district is attempting to fire Maria Saucedo Scholastic Academy teacher Sarah Chambers, for allegedly violating state and city school board policies.

The district would not elaborate on the charges against Chambers, but she said she got an email just before spring break accusing her of encouraging a student to opt out of the PARCC standardized test required for grades 3-8 and high school.

“I was in complete and utter shock. I mean, I’m a distinguished teacher. I’ve been rated distinguished by all six principals I’ve had. I’ve never been written up in my life,” she said. “They wouldn’t even tell me in person.”

Chambers denied the allegations against her, and claimed she’s being targeted because she has been a frequent thorn in the district’s side by fighting schedule changes for special needs students, criticizing budget cuts, and for union organizing.

“There’s really an attack against me, because I’m an outspoken union activist, and especially an outspoken special education advocate. They cut special education by $80 million at least this year alone, and it’s really hurting our students,” she said. “I’ve spoken at the Board of Education, and brought parents and students to speak at the Board of Education, and frankly they want teachers to be silent. You know, they want them to follow their orders, and I can’t be silent, because it hurts my students with disabilities.”

Chambers was one of the CTU organizers of a one-day teachers’ strike last year, and also was arrested in February 2016, after taking part in a sit-in at Bank of America to protest what the teachers called bad investments in CPS funds. In 2014, she was one of several teachers who refused to administer the state-required ISAT exam to students, claiming students are forced to take too many standardized tests.

The Chicago Teachers Union has been fighting to protect Chambers’ job, and she can make her case to keep her job at a hearing before an independent Illinois State Board of Education hearing officer. CTU said that hearing has not yet been scheduled.

Chambers said there already are two vacancies for special education teachers at Saucedo, and she’s concerned what her suspension and possible firing will mean for her students.

“The feeling of not returning to my classroom and my students with disabilities on Monday breaks my heart. I just really worry about my students, and if CPS and Rahm Emanuel really cared about special education, then they would stop this witch hunt,” she said.

More than 2,000 people have signed an online petition supporting Chambers, and urging CPS not to fire her.