Why don’t the police arrest these three goons? Their intent is clear: to obstruct justice by dissuading witnesses under threat of violence.
There would surely be several laws that they are breaking by doing that.
Their attorney, in front of a jury of their peers, could quite successfull argue that it is a message to end shoplifting!
Snitch, even in non-US English, has multiple meanings, and reasonable doubt is easy to instill in jurors who have the same mindset of those "youths".