1999 Mercedes Benz SL500 oil leak

1999 Mercedes Benz SL500 Automatic 60,000 miles I always have my car parked inside my garage. I went out of town for 4 days and when I return my car had just begun to leak oil on the night that I returned. I had not been driven for 2 months. Why would a car that has not been driven for 2 months leak oil. By the next day all of the oil had leaked out. Could there be a possibility of car tampering.