If I was Michal, this dagger would already be back to the dealer that sold it and I woulod have my money back. I would also give Andrea all the information he needs to work with the legal authorities to recover the dagger and find the thief.
In short, I would extricate myself. It is unfortunate that this theft happened, so I would try and limit the damage to those directly involved.
Those directly involved are the owner, thief, and dealer who bought directly from the thief. This is the best way to find the identity of the thief.
Just my opinion
