Immediately we can deduce that these robbers knew who you are and have well-planned this attack so right off the bat we can assume that they did not use a centralized exchange of course that is to say that these robbers are not stupid but let us be honest if people were to know that you own bitcoin, they most probably are well knowledgeable about the cryptocurrency scene

I have heard of stealing bitcoin by hacking but i have just heard now stealing by brute force