2002 Ford Focus Electrical Drain on Battery

My daughters car has a electrical drain on the battery. She called and said her battery was dead and was the original battery. I suggested she get a new one because in my experience anything after five years a battery can short out. I than had her take it and have someone test the alternator just to make sure it was okay. The test showed that the alternator was working fine but there was something causing a draw on the battery with the car key off. Any suggestions of where to start looking and is there something peculiar to the focus that might explain this. On a escort I had I found the problem in the radiator fan coming on while the car was sitting even when it was not hot.

Thanks...........Flurry