Possible leak in window of camper top

I am looking at a possible leak in the rear window (the window closest to the cab) of my camper top.
I found a puddle in the bed of my truck after a rain... I already have weather stripping between the rails of the bed and the camper top. Unfortunately I haven't found a damp spot in the camper top yet (although I'm guessing the window because of where the puddle is)...
Ideas? Will silicone sealant around the window work, you think?

 

I'd confirm that it's coming through the window and not the weather stripping before you do anything. You could have someone spray it while you sit inside or tape some paper under the window but above the bed rail. Weather stripping isn't always 100% waterproof in this application - I've had two camper shells develop leaks between the shell and the rails over time. I imagine it could possibly happen even when it is new by accident. If it is the window you'll still have to pinpoint where it's coming through to see how to fix it.

 

Fair enough. I'll post back.

 

Just crawled up in there ... the fiberglass was dry (it rained last night) but there was water all along the back corners of the bed (closest to the cab) and staining on the fiber glass. I couldn't tell where exactly water was coming in but ...
Here's where the staining was

 

I would use bedding and glazing compound before I used silicone it's what they used with glass and rubeer seals in trucks and cars in the 60s before they started gluing them in