You would be surprised what you can do. Most of the time the only things that prevent people from doing actions like this are societal convention or the feeling that you have too much to lose. These fears are compounded by copaganda that convinces you that detectives will ultimately find out that it was you that committed the act. The truth is that anyone who is knowledgeable and possesses certain resources can perform acts like this with only a small group of people and get away with it, maybe not always with a clean record though.