There were many lawsuits against Gulen and his sympathizers (Hizmet movement) even in US - but he was acquitted many times. Erdogan put all the blame on him and his followers to suppress corruption investigation into his circle of politicians and even family members. Read about Reza Zarrab prosecuted in US right now.

https://www.google.com/amp/www.wsj.com/amp/articles/iran-san...