In a somewhat surprising case dealing with Worker's Compensation (yes, even public school districts have to deal with WC), Pennsylvania's Commonwealth Court rejected the University of Pennsylvania's claim for termination of benefits to an injured employee with a later criminal conviction. Penn's claim was that one of its police officers  was injured, went out on WC, then both recovered and was convicted of Simple Assault and Endangering Children.
Finding first that the police officer/Claimant was still unable to work because he had not recovered from his injuries, the court made the startling statement that Claimant's "certification status is irrelevant because Claimant would not be able to work as a campus police officer regardless of whether or not he was certified."
Softening the blow a bit, the court went on to fashion this issue into a "sufficiency of evidence" argument. That meant that since Penn had the burden to prove any reason to stop compensation, that it should have proved that the employee's certification was actually revoked.
But this is an education blog, and issues surrounding police officer certifications are rarer for us than teacher certification issues. Luckily for us (but not the teacher), the criminal conviction of a teacher out on Worker's Comp would likely prove an intervening/superceding cause in a way that might not have applied in this case.
One way that highlights the difference between a private university and a public school is the applicability of §5-527 of the School Code. That section requires various types of public and private schools (but which excludes Penn) to terminate an employee who is convicted of particular drug offenses or offenses covered in §1-111. Endangering the Welfare of a Child (18 Pa.C.S. §4304) is one of those listed offenses requiring termination.
Beyond the above, there are certainly other ways for a school to deal with this issue, both statutory and contractual, but it is interesting to note how the law differs for different types of schools.
The case is University of Pennsylvania v. Workers Compensation Appeals Board, 2240 C.D. 2010, and can be accessed here.