A teacher with the Morris-Union Jointure Commission lost her tenure and her job working with students with autism because, officials say, she engaged in a pattern of corporal punishment.

The teacher's attorney, however, alleges the commission tampered with witnesses and failed to turn over evidence.

Jennifer Filo, whose dismissal was upheld in a ruling by a state arbitrator last month, allegedly hit students, bent back their fingers and wrists to the point of causing pain, used more force than necessary to restrain students, withheld breakfast from students and hit one student's knuckles with a clipboard while she served as a teacher at the Developmental Learning Center in Warren last summer.

Filo also asked a couple of students "if they were stupid or an idiot," screamed at students on a daily basis, encouraged students to hit back when they became aggressive toward each other and intentionally mimicked students' autistic-like behaviors, according to a 44-page decision by arbitrator Robert Simmelkjaer.

Many of the Morris-Union Jointure Commission's students are on the more severe end of the autism spectrum, such as non-verbal students who require physical prompting to do their work and students with aggressive behavior who can become violent, according to Simmelkjaer's decision.

The school operates on a 10-month extended school year, but it was largely Filo's alleged behavior from June to August 2014 on which the arbitrator's decision focused.

Filo, who was hired as a full-time teacher in Sept. 2006, served as a teacher for the commission at the New Providence location during the regular school year and at the Warren facility during the extended school year.

During the summer program, Filo had eight students in her class -- all but two of whom were non-verbal -- and four teaching assistants, according to the decision.

Three of the four teaching assistants later testified against Filo, who has denied the charges against her and alleged the commission engaged in "witness tampering."

Filo's attorney, Timothy Smith, said the one teaching assistant who didn't testify against Filo was the first one to be interviewed by the commission's counsel and was terminated by the commission shortly thereafter. He alleges the commission's counsel laid out its case against Filo at the beginning of the interview in order to signal the direction her testimony should proceed.

According to Smith, the commission initially denied the existence of a tape recording of this interview, but later produced it. Based on this procedural issue alone, he said, the arbitrator's decision should have been thrown out.

The arbitrator's decision indicates a teaching assistant was terminated from her employment this past October "based on conduct similar to that alleged against Ms. Filo."

"If this abuse had really happened, it would have triggered reporting obligations (by the teaching assistants)," he said.

Smith said investigations by the police and the state division of Child Protection and Permanency failed to yield any charges against his client. No parents testified against Filo, but one parent testified in her favor, he said.

The other three teaching assistants who testified against his client, Smith said, were also interviewed in the same room at the same time and given packets containing each others' statements. Smith alleged the three teaching assistants, all of whom are non-tenured, testified against his client because they feared losing their jobs.

In his decision, Simmelkjaer said the three teaching assistants had "a genuine, albeit unfounded belief, that the reporting of any abuse incidents could redound to their detriment," and ruled that their "unreasonable fear of retaliation" didn't affect the credibility of their testimony.

The arbitrator also said he found no evidence the teaching assistants had altered their testimony from their initial certifications or were asked to put things in their statement "that were untrue."

Robin McMahon, counsel for the Morris-Union Jointure Commission, said the commission had complied with discovery rules and that Filo and Smith's allegations of witness tampering were a "bogus defense" and had "no substance." McMahon also said Smith "engages in numerous allegations of questionable validity."

"It's not witness tampering, it's witness preparation," she said.

The audio tape of the interview, McMahon said, was in the teaching assistant's personnel file -- not Filo's -- so it was initially overlooked.

In his decision, Simmelkjaer found there was "no evidence of procedural irregularity or appearance of impropriety that would warrant the dismissal of charges or specifications on procedural grounds." The arbitrator also held the commission "met its burden of proof by a preponderance of the credible evidence that Ms. Filo engaged in conduct unbecoming or other just cause manifested in a pattern of corporal punishment and excessive force prohibited by commission policy and state statute."

The arbitrator sided with the commission in finding that Filo's dismissal was "the only appropriate remedy."

"The gravity of her misconduct, her use of excessive force, and the absence of extenuating circumstances render her unfit to teach," Simmelkjaer said in his decision. "(Filo's) lack of remorse for her use of excessive force and failure to acknowledge that any of her conduct was inappropriate militate against the imposition of a lesser penalty such as suspension coupled with retraining."

Smith has not yet filed a challenge to vacate the arbitrator's decision, but said he still has time to do so.

McMahon said "at the end of the day" Smith didn't have a basis for appeal.

Justin Zaremba may be reached at jzaremba@njadvancemedia.com. Follow him on Twitter @JustinZarembaNJ. Find NJ.com on Facebook.