Stalkers may be using apps to stalk and harass Targeted Individuals. These app could come from "Unknown Sources" outside of Google Play and Amazon App stores.
Android allows developers, or whoever sees fit to use the feature, to install apps from "unknown sources". Amazon uses this feature. and this is how they have implemented the Amazon App Store for Android devices. As big as Organized Gang Stalking is, they can have developers and investors develop apps and an app store where they can update and distribute apps and communicate and stalk and harass Targeted Individuals.
This possibility is an explanation for some of the stalking and behavior. But doesn't explain all as I've seemingly experienced behavior that is inhuman and more consistent with telepathy and even telekinesis.