Bitcoin maybe decentralized but if a crime is committed against any country or under there law they can confiscate the stolen Bitcoin when the lay their hands on it.
Bitcoin is decentralized but is not above the law and any crime caught using Bitcoin will face the normal judiciary procedures.
Only if the Bitcoin is stored on a centralized exchange or custodial wallet. Governments simply can't confiscate non-custodial Bitcoin. The criminal would be smart enough to store his BTC on a non-custodial wallet hidden from plain sight. He'll be able to recover the coins after he completes his sentence (if caught). Depending on how long that sentence is. Because if it's a lifetime sentence, then the criminal won't be access it for good.
Even though Bitcoin is decentralized, that doesn't give you the right to do anything with it (as in doing anything "illegal"). There are rules/laws for a reason. And we must respect them. Fortunately, Bitcoin's transparent design, allows authorities to track down criminal activities on-chain. It's more of a feature than a bug to me. For the true privacy paranoid, Monero and similar coins would be the ideal choice. Abide by the laws imposed by the government, and you'll have nothing to worry about.