1999 Ford Fiesta Water

Hi, My problem is not really mechanical, it is as follows,
the car was parked up for one week while owner
was on holiday, after heavy rain there was about 2
inches of water on the floor at the front passenger
seat, windows and doors were tightly closed, I, ve
looked high up and low down but cant find where
the water got in, and is still getting in. Any ideas?