Remember COINTEL pro in the 1960s. The Federal government engaged in illegal activities targeting numerous individuals including Martin Luther King Jr. Malcolm X, and others. Well, what I am describing is the modern version of it that is going on today using technology to obfuscate the origins of the attacks, and to provide plausible deniability so that without a careful review it is difficult to even discern but by the person targeted.
These same techniques are utilized to communicate covertly as well as to engage in highly targeted intimidation and harassment campaigns. Who are cooking up these methods? Intelligence agencies. The crafters must first get inside the mind of the target (so a target profile) is required for the campaign to be properly. This requires 24/7 eavesdropping, going through the target background (email accounts), records, anything that will add to the profile, and this is supplemented with physical surveillance.
Once the profile is crafted they move into creating a campaign. Cognitive anchors are established crafted to facilitate target acceptance. This is done via ensuring the target will view (i.e. placement) of the cognitive anchor and the message (fear mongering, threats, etc or direction).