What if employee A makes up lies about employee B, and the reason a bunch of other people feel uncomfortable or unproductive or unhappy around employee B is jus

What if employee A makes up lies about employee B, and the reason a bunch of other people feel uncomfortable or unproductive or unhappy around employee B is just based on perception from these lies? Are you in the right as an employer to fire employee B without serious due diligence? To potentially ruin employee B’s life or reputation? Instead of letting it escalate to a real court case (if applicable)?