While others are tailoring their answers to a sedan, and you appear to have a wagon, the rear window seal on the rear hatch is a known leaker too. Same thing applies with adding sealer around the seal/glass area. I've had to do that with Smash and have stopped a leak on one side. Now I have to address the other side...

__________________
Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John