Still have a small water leak.

I have been chasing a leak for a while now. First it was my back window gasket....Fixed that. Then I found out that my vapor barrier on the back passenger door was loose and I fixed that. Now I have an area behind the back seat that is still getting a few drops of water. I will attach a picture pointing with a screw driver to show the area. I sealed the crack where the back of the cab meets the floor and the rubber plug with lexon sealer or whatever it is called. It is not coming from up above that I can tell. Fabric on the back wall is completely dry. I have been under the truck and all the welds look fine. I even sealed the back cab vent on the passenger side by the bed of the truck. Anyone else have any ideas?