One of the benefits (and concerns, depending on which side of the fence you’re on) about Bitcoin is the level of anonymity that you get, along with the ease of moving money between Bitcoin wallets. With that in mind, you can understand when a stash of at least 5,400 Bitcoins were stolen, it caused a furore. At the time, 5,400 of Bitcoins would roughly be worth slightly above $5.4 million.
While Bitcoin can hide your identity, Bitcoin wallets are public record, which allowed a bunch of folks on Reddit to try and trace the stolen Bitcoins. It’s a long story, and the chase included following a wallet with 96,000 Bitcoins (about $100m), but in the end yielded nothing.
Tracing stolen money is never easy, so it wouldn’t be too surprising if the stolen Bitcoins are unable to be recovered.
Small bitcoin transactions can be laundered using a “tumbler”, which takes money from multiple sources, mixes it all together in one wallet, and spits it out the other side. Someone following the cash sees it get split and recombined over and over, until it’s impossible to separate from the money being tumbled by other users.
But that plan falls apart when trying to launder $100m of bitcoin. What the bitcoin thief found was that the sheer quantity of cash they were tying to hide overwhelmed every other transaction being tumbled at the same time: 96,000 bitcoins went in at one end, and 96,000 came out at the other. It seemed like their money had been successfully traced to one final address where it eventually came to rest.