leak coming from passenger taillight

[scumfromohio]

Bought my chick an 08 xd. The passenger taillight had a hole in it. We noticed the car started to smell like mold. Inspected and there was a very large lil of water in the hatch/spare tire area and had also splashed in to the rear seats for area. We drained it cleaned everything got a new taillight and sprayed the car down to see if it was just the taillight. And it wasn't its leaning from right above the taillight but dripping into the hatch not into the taillight. Is the weather strip bad. There's a maybe 3 inch rubber square right above that I was wondering if it was bad. Anyone had this problem before???