Case lost in African expedition miles away (4)

I believe the answer is:

afar

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'miles away' is the definition.
(far away)

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

(Other definitions for afar that I've seen before include "from baseline to baseline?" , "quite some distance" , "Distant parts" , "Distant, not near" , "beyond the horizon" .)

I've seen this clue in The Times.

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