Detective's lead (4)
'detective's lead' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for clue that I've seen before include "Crossword help" , "contribution to crossword" , "one of 28 here" , "Indication, hint" , "One of twenty-four in this puzzle" .)
(Other definitions for tip that I've seen before include "Point; hint" , "single piece of asparagus, perhaps" , "expected by those who wait" , "Bonus" , "Useful hint; end" .)