For Jehovah's Witnesses ONLY?

Ok I know this is not the proper channel to ask this, but I am in a quandary. I have recently been made aware of serious wrong doing on the part of a close family member. The person is now married to his "partner in crime". This person lives about 2000 miles away and that is where the wrong doing took place. I am certain that my family out there knows nothing of what happened. What do I do? I don't want to inform my local elders here, or anyone in my congregation for that matter, as this person is well respected and well loved. I also do not want to create a rift in my family, or be accused of "murmering". I really don't know what to do. The wrong doing is serious and took place several times. What is my responsibility before Jehovah in this matter? Obviously, I was not an eye-witness to the wrong doing, I doubt there were any, or any in his congregation who know. I am really upset about this, what do I do?