There is no doubt that all four accounts have read your message and seen this thread, but he or they have chosen to ignore it and not reply. I think this may also indicate they are linked together.
There's absolute no reason to believe they're linked simply because they all have ignored the message. That's not evidence, that's just a correlation, <cut>
No ... I didn't think it was evidence. It just seemed unlikely that all four would ignore this topic and personal messages from other members, despite being active in the forum. Though I agree that I could have worded it differently.