Insignificant people, evidence of their murder missing? (8)
I believe the answer is:
nobodies
'insignificant people' is the definition.
(I've seen this before)
I don't understand the remainder of the clue.
(Other definitions for nobodies that I've seen before include "Unimportant people" , "People without importance or authority" , "Ciphers" , "Insignificant people" .)