Husain ibn Ruh Nowbakhti, who is considered by the Twelver Shصah as the third special deputy to their 21th Imam, spent five years of his lifetime, 429 ه 929 AD, in the prison of al ه Mughtadir, the Addasid Khalifah. This article takes up the two reasons often cited for his arrest: 1. Refusal to pay what the government demanded of him. 2. Cooperation with Qarmatian. The article confirms the first and rejects the Second reason. In addition, a third hypothesis has been brought up here; that is, the Ghulat )Exaggerators( conspired and provoked the Abbasid establishment to arrest him.