To "case a
joint" is to check out the details to, and make speculations about, a home, car,
store or other location for means of getting in undetected and/or removing material from said location.
Usually referred to negatively as a means to describe being suspicious someone is going to
steal someone's belongings, it can also simply be a synonym for reconnaissance.
1. That
banger over there was casing the joint when I came in this morning.
2. Tell Tommy to
go case the Sanders' joint and see if Paulie's car is there.
3. I saw you going out to case a joint earlier, you
better not take anything.