PLACERVILLE, Calif. -- Two private school administrators and a teacher are facing criminal charges in the death of an autistic student who was restrained for nearly two hours, prosecutors in Northern California said.

Former Guiding Hands School site administrator Cindy Keller, principal Staranne Meyers and special education teacher Kimberly Wohlwend were scheduled to be arraigned Wednesday on one count each of manslaughter in the death of 13-year-old Max Benson, the Sacramento Bee reported.

District attorney's officials said lawyers for the three were co-operating with prosecutors. The names of the attorneys were not immediately available.

Benson became unresponsive while being held in a "prone restraint" for nearly two hours at the school and died a day later at a hospital, authorities said.

State education regulators found evidence that staffers at the El Dorado Hills school used an unreasonable amount of force and put Benson in restraint for longer than necessary. The staff's actions were harmful to the health, welfare or safety of the student, the state inspection stated.

Court documents and state records show Guiding Hands had been the subject of several state investigations over its treatment of special-needs students. The school closed in February after state education officials withdrew its certification.

A separate civil lawsuit filed against Guiding Hands on behalf of Benson's family and other families of Guiding Hands students alleges Wohlwend held Max's upper body while other staff members took turns holding the boy's legs down.

Prone restraints are used in California schools, often on students with special needs, but legislation signed by Gov. Gavin Newsom last month allows the state Department of Education to suspend or revoke a school's certification if a student's health or safety is being compromised.

Stacia Langley, the boy's mother, told the newspaper she wanted to protect other people from experiencing a tragedy like her son's.

"Max would want to protect other kids," she said. "He wanted to be a hero. He's finally going to be a hero."