Looked a joint over (5)
I believe the answer is:
'looked a joint over' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for cased that I've seen before include "put in a box" , "examined with intention to rob" , "Covered, protected; checked over (by robber)" , "Reconnoitred (sl.)" , "Carefully inspected (for crime)" .)