I would welcome expert correction here.
The slight research I've done here suggests that from a legal perspective, it's safer to terminate than not, even if you're concerned about the veracity of the accusation.
I'm going to repeat that we're in firm agreement about not firing "for cause". You don't need cause to fire employees you've competently hired. It is definitely legally risky to provide negative references that include accusations of tortious behavior! Minimize drama, by all means.