CHAPEL HILL, N.C. — A Chapel Hill teacher who was honored for her accomplishments is accused of assaulting two autistic students.

Kathleen Yasui-Der was arrested for assault and contributing to the neglect of a minor. Investigators say the charges are tied to events in May, involving a 9-year-old and 12-year-old boy at Frank Porter Graham Elementary School. Police say Yasui-Der bent a student's finger and twisted another student's arm.

Some parents were shocked to hear the allegations involving Yasui-Der.

"Kathy is a kind, gentle consumate professional who accomplished so much in the years she taught," parent Alice Wertheimer said. "She was devoted to her students, and loves her students and dedicated her life in a field that was very challenging."

After 12 years in the classroom, Yasui-Der resigned from her teaching job in July. She was teacher of the year at Frank Porter Graham in 2002 and the recipient of the Dean Smith Teaching Award last year.

Yasui-Der was also instrumental in bringing an autism program to Chapel Hill schools more than a decade ago.

Many parents and co-workers said they intend to mobilize and help with Yasui-Der's defense.

Parents of children who were in the class will be told about results of the investigation as it pertains to their child. Yasui-Der was not at home Wednesday for comment. She is expected to be in court in September.