What is the religious ruling on a person who spies on someone afflicted with a sin, exposes him, mobilizes others to spy on him, and verbally abuses him, and what is his punishment?

This person has violated the Shari'ah by spying on and tracking the faults of a sinner and shaming him for them. The Shari'ah has threatened severe punishment for those who do this, even exposing them "in the inner confines of their dwelling." The believer conceals and advises secretly, while the wicked exposes and shames. Reproaching and shaming someone for their sin is condemned in Islamic law, and "whoever shames his brother for a sin will not die until he commits it himself." This person must repent and apologize to his brother, and the sinner must repent to Allah Almighty.