The perfect theft in crypto is claiming that a project or an exchange is hacked when its all an inside job, the reason why I think about this is I have never heard about other top exchanges helping a exchange that just got hacked to track their funds and get some back at least but if it's a sole hacker from outside they will track him or them down, why is that?.
One example of how this inside job scheme happens,
https://dailyhodl.com/2019/04/01/inside-job-19-million-bithumb-hack-exposes-major-problem-with-cryptocurrency-exchanges/But never did I think this involve the owner itself, it was their staff, who does the work and secretly do the transfer.
In some cases, this becomes a dirty tactic that mostly happens to scam sites, they pretend to be hacked and announced it publicly but the truth is that...it was an exit scam. Many exchanges have been doing this thing and a reason that we have to use reputable exchanges.