I understand you are fustrated that you spent a lot of time
finding the avatar. But there is a
small possiblility that
the person did find it themselves, though. It is jumping to
conclusions, saying they stole them from you. Maybe they
did, maybe they did not. Who knows?
The real answer, of course, is
If I were you, I would just take down the whole avatar
section on your page. That way you do not have to worry
about anything like this ever again, savvy?