Feral big cats

The ‘Lithgow panther’ in the news again. This one comes around every few years – here’s an SMH story from 2003.
The last “Big Cat” turned out to be just a “big cat”, but the evidence is mounting. And why not? If escaped wallabies can live happily in the English Peak District, I’m sure escaped panthers/pumas/jaguars (delete as appropriate) can survive in the Blue Mountains. Why don’t they just get this evidence out in the open for all to see and assess?