I believe they have been here for thousands of years. I think that cats came here with the Phoenicians and Asians as well as the Egyptians. Boats carried cats to keep rats away from food. Ships sink, cats are survivors and they could easily come ashore when boats docked here. (There is a description of a kangaroo in a document listing the animals in one of the Chinese Emperors zoo's going back many, many hundreds of years.) Ferals keep getting bigger and bigger and with a small genetic pool back then, it is not out of the question that they would grew to the same proportions of their African cousins. Then you can through the released big cats into the mix. That is why you have conflicting descriptions and DNA from some samples comes back as domestic cat. They are, they are just really, really big.
Other samples have come back as leopard, but media tends to ignore these, or they are deliberately mis identified.
