Complex sentence: Anonymous letters purporting to be from a one of a gang of culprits named 27 year old Edaji and schoolboys who Edalji regularly commuted in the same train compartment with including 15 year old Wilfred Greatorex.
Split into simpler sentences: Anonymous letters purporting to be from a one of a gang of culprits named the gang members. The names turned out to be of schoolboys who Edalji regularly commuted in the same train compartment with, including 15 year old Wilfred Greatorex.