there is this

http://www.informationweek.com/security/attacks-and-breaches/mt-gox-chief-stole-100000-bitcoins-hackers-claim/d/d-id/1114197

and that

http://www.theguardian.com/technology/2014/mar/14/mtgox-knowingly-traded-non-existent-bitcoins-for-two-weeks-filing-shows