Unimportant persons found after well-planned murders? (8)

I believe the answer is:

nobodies

I'm a little stuck... Click here to teach me more about this clue!

'unimportant persons' is the definition.
'nobodies' can be an answer for 'persons' (nobody is a kind of person). I'm unsure of the 'unimportant' bit.

I don't understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for nobodies that I've seen before include "Unimportant people" , "People without importance or authority" , "Ciphers" , "Insignificant people" .)

I've seen this clue in The Guardian and The Globe and Mail.

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