Unknown problem encountered in solving murder? (6)
I believe the answer is:
nobody
'unknown' is the definition.
(I've seen this in another clue)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for nobody that I've seen before include "Ineffective person" , "The Diary of a --- (George &Weedon Grossmith)" , "Unimportant person" , "The Diary of a - - (G & W Grossmith)" , "Person without influence" .)