A lawyer for a New Jersey teacher accused of mistreating an autistic boy called the father's claim "inaccurate," saying his client had no part in the alleged abuse caught on a secret audio tape.

Stuart Chaifetz is calling for teacher Kelly Altenburg's license to be revoked after a secret wiretap of his 10-year-old son allegedly showed school staff berating the boy in Altenburg's classroom. The tape, which has since gone viral, recorded staff calling the autistic child a "bastard" and telling him to "shut up."

But in a statement released to FoxNews.com, Alternburg's attorney said his client's voice is not heard on the recording and claimed she had no knowledge the remarks were made inside her classroom at Horace Mann Elementary School in Cherry Hill.

"Mrs. Altenburg does not condone any such remarks detailed above and this language was not used at her direction, in her presence or with her knowledge," attorney Matthew Wieliczko said in a statement. "Mr. Chaifetz' comments to the contrary are totally inaccurate." Wieliczko went on to say that Altenburg was absent from her classroom for at least an hour on the day the tape was made.

Chaifetz planted the secret digital audio recorder on his son, Akian, on Feb. 17, after he suspected school staff was bullying the child. Chaifetz said he had been receiving reports that the boy was hitting his teacher and an aide -- a claim he said "didn't make any sense to me because that’s not my son."

"I knew, as a father, that there was something going on inside that classroom that was affecting Akian badly enough that he would be hitting a teacher," Chaifetz told FoxNews.com Thursday.

Chaifetz said he and his ex-wife were "shattered" after listening to the seven hours of tape. In addition to verbal abuse spewed at his son, school staff can be heard taking about being hungover.

As of Friday afternoon, it remains unclear whether Altenburg has been fired. In the latest statement posted on the district's website, "all individuals working in the classroom on the date in question have been either been placed on leave to minimize disruption to our schools, or no longer work for the District."

"New Jersey law provides protection to tenured employees against immediate dismissal," the statement said.

On Thursday, a spokesman for the New Jersey Teachers Association told FoxNews.com that Altenburg was transferred to another school within the district.

"The teacher’s voice is not on that recording," NJEA spokesman Steve Wollmer said. "It’s not her voice. It’s a teacher aide and somebody else."

Chaifetz claims district officials told him a teaching assistant he identified as Jodi Sgouros was fired immediately after administrators listened to the recording in February. But he says he received no word about any punishment meted out to Altenburg.

Unsatisfied with the district's handling of the matter, Chaifetz recently went public with the tape, posting a 17-minute long video on YouTube titled "Teacher/Bully: How My Son Was Humiliated and Tormented by his Teacher and Aide." He then posted a follow-up YouTube video on Tuesday, calling out school officials for not firing Chaifetz.

He told FoxNews.com that Altenburg, a 25-year special education teacher, should be punished even if her voice is not heard on the recording. His son, he said, was exposed to a "culture of cruelty." 

"Would they have called my son a 'bastard' if they knew he could come home and tell me?" Chaifetz said. "They thought I would never find out."