Suspect Harry is holding back in Scotland Yard (5)
I believe the answer is:
dodgy
'suspect' is the definition.
(I've seen this before)
'harry is holding back in scotland yard' is the wordplay.
'harry' becomes 'dog' (I've seen this in other clues).
'is holding' indicates putting letters inside.
'back in' suggests the final letters (the 'back' of the word).
'yard' becomes 'y'.
The last letter of 'scotland' is 'd'.
'dog' placed around 'd' is 'dodg'.
'dodg'+'y'='DODGY'
(Other definitions for dodgy that I've seen before include "Dubious; dicey" , "Of doubtful quality or legality" , "Not reliable; dangerous" , "fishy!" , "Unreliable" .)