EL DORADO COUNTY (CBS13) — The three women charged in 13-year-old Max Benson’s death appeared in court Wednesday.

All of the defendants entered not guilty pleas. Max, who had autism, died last year after being physically restrained at Guiding Hands School.

Former Guiding Hands Executive Director Cindy Keller, Principal Staranne Myers, and teacher Kimberly Wohlwend.

Former Guiding Hands Executive Director Cindy Keller, Principal Staranne Myers, and teacher Kimberly Wohlwend are all charged with involuntary manslaughter. The judge ordered they cannot teach or work with children.

The corporation that owned the Guiding Hands School is also facing a manslaughter charge.

Guiding Hands is now closed, but the owners and former employees now face what could be a lengthy battle in court.

READ: Family, Friends Seeking Justice 1 Year After Death Of 13-Year-Old With Autism

As the three defendants walked into court Wednesday, all looked away from the media, ignoring questions and cameras.

Max’s parents and family walked out of the courthouse holding hands. It’s been a year since they lost their son. The family declined to speak but referred CBS13 to their family attorney, Seth Goldstein. He says the way Max died is more common than you would think, going as far as to say it’s becoming an “epidemic” in schools.

Teacher Kimberly Wohlwend was identified as the person who restrained Max last year. Up until this week, she was still teaching at another local school.

The state Department of Education determined nearly a year ago that the restraints used prior to Max’s death violated state law. But Wohlwend, who is now charged with involuntary manslaughter, is still credentialed by a different state agency and has been legally allowed to continue teaching special education.

Wohlwend’s special education and elementary teaching credentials do not expire for more than a year, and the California Commission on Teacher Credentialing shows no record of action against her.

READ: Candlelight Vigil Being Held Sunday For Max Benson

The agency says they cannot automatically revoke a teacher’s credentials without an investigation unless the teacher is convicted of certain crimes, is a sex offender, or found to be insane by a court. They say it’s up to the school districts to keep credentialed teachers out of the classroom based on behavior that is under investigation.

As of Wednesday, Wohlwend is still employed as a special education teacher in the Pollock Pines School District. In court, Wohlwend’s attorney said she stopped teaching at Sierra Ridge Middle School two days ago.

The middle school released a statement saying, in part, that they can’t comment on an employee facing criminal charges, but said student safety is their primary concern.

CBS13 asked the Pollock Pines superintendent and the school board about their hiring practices and how they background check teachers but did not hear back in time for publication Wednesday.

The teacher credentialing commission cannot confirm or deny whether it is investigating Wohlwend until the investigation is complete.