1992 Honda Civic trunk leaks; not the taillight

I have read all the messages re: leak in the trunk. I have checked seals at taillights etc. all appear in good shape. Water accumulates [passenger side] on the ledge ABOVE the taillight housing. The body panels directly above and beside this ledge are dry. I am now thoroughly baffled! There is a deep indentation on the fender side of this ledge. Is there some sort of drain hole or some such that could be siphoning water in? thanx - bobby d