AMHERST, Mass. (AP) — A former Amherst Regional High School teacher who was the target of racist graffiti has filed a complaint with the Massachusetts Commission against Discrimination.

The complaint filed Monday by lawyer for math teacher Carolyn Gardner said school administrators mistreated her by placing her on unpaid medical leave after she had been diagnosed with post-traumatic stress disorder.

Gardner, who is black, has not taught at the school since May after racist messages and graffiti targeting her were found around the school during the last year. No one was ever charged with writing the messages.

Her lawyers say the complaint was filed after school officials determined that Gardner's allegations of mistreatment as baseless.

Superintendent Maria Geryk said she had no comment about the complaint.