Thanks for all the feedbacks. The trunk seal looks fine(no cracks, no rust), nor did I see any leakage when I put myself inside the trunk as Threadcutter suggested. On the other hand, it's not easy for me to maneuver inside the trunck, so I could miss the spots.
Anyway, this weekend, I am going to pour some water around the trunk seal and see whether there is any leak. I will keep you guy updated.
-->Henry