Forgot to trade an item during a transfer

[Ssirol]

I found in my inventory an extra item that I'm pretty sure I didnt loot or buy. People often ask me to transfer their item from a char to another. I didnt forgot this item in purpose and I would like to give it back to its owner.

If you are the owner, you should be able to answer to these questions :
What is the item ?
When and where the trade occured and what were the other items ?