It is one command on electrum. Anyway, you didn't answer my question. Yes, mixers is a good solution for the hacker, but can someone prove that he owns the addresses?
It quite obvious because when the hacker tries to cashout to fiat. That's when problems come in. Remember, almost all big crypto to fiat exchanges require some sort of KYC. Most are centralized and can handover KYC details, email addresses plus IP logs to the authorities when they trace the transactions to the exchange's address.
That's an answer. Thanks. I didn't know that police is searching for bitcoin scammers.
If you didn't know, then know it from today. Here is a perfect example of how the twitter scam hackers were arrested, they tried to cashed out their unmixed stolen bitcoins -
https://www.digitaltrends.com/news/tampa-teen-twitter-bitcoin-scam-arrested/