Tornado cash
Unless I'm mistaken, proceeds of a theft can be seized and given back to the rightful owner regardless of whether the current owner knew about their origin — if a bicycle is stolen and resold to an unsuspecting buyer, it nevertheless belongs to the original owner, and it's technically on the unsuspecting buyer to get their money back from the thief.
The point of tornado cash is to mix and obfuscate the origin of the cryptocurrency, but the blockchain still remembers the origin of every single token. From the principle above, it would make sense to seize the exact tokens that were stolen, regardless of who's supposed to own them — as the process of theft, the legal ownership is still with the stolen party.