1999 camry le

The final resting place for a leak can be a fair way from the source. The body has lots of ridges and channels where spot-welding is done. These can act as a conduit for the water,..so the best way is to remove the back seat and see f there are any witness-marks.

Maybe the door seals or even the trunk. Water leaking in thru the trunk can flow down the wheel arch into the cabin>> to the floor.

As a test: As the car is newish Id take out the rear seat and sit in there with the car closed up and an assistant spraying water on the back.

Jason