More than likely the trunk seal. Mine leaks there too. But there are leaks around the top corners of the front windows. I just park it with the front end a little higher than the back
Works for the trunk but not the windows. I also park it at the house under a "shelter". I found that driving it in the rain, I turn on the a/c or just fresh air and put it in the fresh air mode, not recirculate. With the fan on med or high, it seems to blow OUT the windows keeping me dry.