The radical cleric Abu Hamza al - Masri served as its imam from 1997 to 2003 .
Abu Hamza al - Masri was convicted for terrorism - related charges in both the UK and the United States .
The radical cleric Abu Hamza al - Masri , who was convicted for terrorism - related charges in both the UK and the United States , served as its imam from 1997 to 2003 .