Interesting that Silkroad actually had 50K bitcoin and more in its custody (not sure if thats the right word) around the time that they were stolen.
Special Agent in Charge Tyler Hatcher, of the Internal Revenue Service – Criminal Investigation, said Zhong used a “sophisticated scheme” to steal the bitcoin from Silk Road. According to the press release, in September 2012, Zhong created nine fraudulent accounts on Silk Road, funding each with between 200 and 2,000 bitcoin.
He then triggered over 140 transactions in rapid succession, which tricked the marketplace’s withdrawal-processing system to release approximately 50,000 bitcoin into his accounts. Zhong then transferred the bitcoin into a variety of wallet addresses all under his control.