Gangstalking is a phenomenon that has grown with the Internet, it is identified only by persons who claim to be targeted, and the descriptions of it provided by self-identified targets are entirely consistent with the experiential symptoms of persecutory delusions.
Gaslighting, stalking, bullying, harassment and other forms of abuse all have one or very few abusers, and abusive acts that can be objectively identified and understood as having the potential to cause distress or harm. Such conduct may be criminally actionable. In “Gangstalking”, according to self-identified targets, anyone and everyone could be or is involved in the abuse, and the abuse takes the form of, eg, driving past the target's house in a particular coloured car, having shopping malls full of abusers all trying to look as if they are out shopping, but who are whispering special key words and phrases and making eye contact with the target, all of which, they know, will let the target know that they are being gang stalked, or driving an emergency vehicle along a road each time the target is walking along it, or moving their keys to somewhere other than where the target remembers putting them down.
Gang stalking leaves no evidence, and includes activities that are, to an objective bystander improbable, implausible, impossible or downright bizarre. All the behaviours that self identified targets regard as part of the campaign against them can be and no doubt if they were investigated, would be explained away as strangers going about their own business with no knowledge of the target's existence.