In this day and age, I would bet one of the first places police look is social media sites, and if they can find them, public posting anywhere on the net.
bob
You would win that bet. Social media and internet postings are a huge source of materials used in criminal and civil cases. IIRC, there was a study done by some family law journal a few years back that said social media was the #1 source of discovery materials in divorce cases.
IMO, internet ramblings and rantings aren't going to turn a good shoot into a bad shoot. What they will do, is be used if it is an iffy shoo or a bad shoot. In those cases, expect all that stuff to be dragged out in front of the jury to paint the defendant as some kind of vigilante or nut job.
As for hanging horse thieves, in the past, all felonies were punishable by death. I am not sure we want to bring that back.