Information from reduced officer (3)
I believe the answer is:
I believe this clue is a double definition.
'information' is the first definition.
(gen can informally mean information)
'reduced officer' is the second definition.
(abbreviation for general; 'reduced' suggests a short form)
'from' is the link.
(Other definitions for gen that I've seen before include "Information (colloq.)", "Information yielded", "Knowledge", "Informal information", "Lowdown (sl.)".)