Fast runners, crooks did you say? (8)

I believe the answer is:

cheetahs

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'fast runners' is the definition.
(I've seen this before)

I cannot understand how the remainder of the clue works.

(Other definitions for cheetahs that I've seen before include "Fastest mammals on land" , "animals" , "Swift, long-legged cats" , "The aches one gets from big cats" , "Swift spotted cats" .)

I've seen this clue in The Times.

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