Video: Stolen Bitcoin Tracing - Computerphile; practical way to trace stolen bitcoins
This is one thing that maybe a few crypto cheerleaders do not always understand when they claim that the anonymity is such a big bonus. There are always inputs and outputs to the system, transparency is at the very core of how Bitcoin works which is a good thing for all honest users. However if you have bad intentions it is easily possible to trace stolen bitcoins and things like mixers are not always an effective choice - you'll often be receiving back money with illicit connections. When you go to cash out, either buying products at a shop or into an exchange, you'll be identified at that location which can make 10 wallet hops to hide it totally ineffective. There are plenty of cases where people have been caught even after all sorts of money laundering attempts.