What is the crime he committed, exactly? Wasn't he simply using a "feature" of Silk Road, ie. if you double-click "withdraw" it prints you money?
I asked my gf's dad, a lawyer, if I could spend it. He said no: it's like someone parking their car on your driveway. It's annoying, sure. But it doesn't make it your car.
A friend of mine is addressing a similar situation right now. After her mother passed away (nearly 20 years ago) and left no will, her primary bank account was still active and the Social Security Administration[0] kept sending her checks every month.
She was notified a few weeks ago of the existence of this account (which now has several hundred thousand dollars in it). Since Social Security benefits (except in specific circumstances[1]) are not collectible by surviving relatives, the moneys paid into that account since her mother's death are not hers (she and her siblings are the only surviving next-of-kin). Rather those funds are the property of the US Government.
In such a circumstance, the funds deposited, as well as any interest on those funds belong to the government.
Transferring those funds or spending any of the interest is a crime.
As such, if you find yourself in a similar situation, I'd think twice before doing something like that.
[1] https://www.cnbc.com/2021/08/16/heres-what-happens-to-social...
It… is.
The difference is that the bank (1) is often in a better position to automatically recover funds from you when they discover an error than vice-versa, (2) has better resources for collection via civil process if they aren’t in a position to automatically recover funds, and (3) has better connections with law enforcement to use if there is any indication of a criminal exploit.