Anytime you accuse someone of anything, you need to make sure you have evidence to back it up. That evidence could include physical witnesses, written evidence, or even footage of someone caught in the act of what he or she has been accused of. Whatever evidence you have, make sure it can stand up in a courtroom and won't buckle under any type of pressure.
An accusation of any kind is very serious, because not only are you questioning someone's integrity, but you are putting their reputation into question as well. When you do that you are putting your own reputation on the line as well. It's common knowledge the accused will shoot down any accusation you are pointing their way, and it turns into a standoff of two people calling each other liars. Whoever is found in the wrong will be seen as a liar to the public.
If you are accusing someone of something and you have a shady past yourself, I would caution you if you choose to further proceed. For example, if this is some type of high profile incident with two people of celebrity status, you can best believe there will be some dirt digging. From there, it becomes a mudslinging contest.
It is in the best interest of both parties to make sure they are not in any way vulnerable to front page slander. I say that, because the public, at times, chooses not to always wait until the final verdict has been handed down. Occasionally, they will assume you are guilty based on what the papers say. No matter if you are innocent or guilty; if you land on the front page you are going to need reputation management, both online and in the media.
Online reputation management is very important because it helps restore your positive reputation you had before you were unceremoniously dragged through the mud. It will help restore your business profiles as well. People who have had a negative opinion of you in the past now see you differently and will want to do business with you again.
Repairing your reputation will take a lot of work, especially if you have been accused of some sort of ethical violation. Whether you are guilty or not remains to be seen, but no matter the outcome, you need to make sure you can salvage and repair what is left of your reputation.