I can give the username and irc channel but I will only give it to people who want to really investigate, I also lost bitcoins on mtgox and trust me I don't want people to buy my own bitcoins, I only bought 50 BTC which is my limit and it covers some 70% of my mtgox losses.
I want this guy denounced to the authorities if he did steal the coins but I didn't do anything, i don't disclose my details here
Give your info to Olivier Janssens, whose contact info is here:
http://www.mtgoxrecovery.com/http://blog.mtgoxrecovery.com/He claims to have retained a very good Japanese law firm to represent gox victims, many of whom have apparently already signed up via the above sites. Perhaps he will want to investigate your claim. If not, maybe he can point you in the right direction.