It's exactly what it sounds like - a criminal prosecution pursued by a private person. This is possible because otherwise, you are at the whim of the Crown (or

It's exactly what it sounds like - a criminal prosecution pursued by a private person. This is possible because otherwise, you are at the whim of the Crown (or in the USA, the District Attorney) as to whether or not a crime gets prosecuted. It doesn't seem equitable for a crime to be committed but never prosecuted because the government doesn't care, or doesn't have the resources to do so. The same standards of evidence apply. It's rarely invoked (but not unheard of), and given how topical Chesa Boudin is at the moment, you can see the reasoning.