Shapeshifting feral cats

You maybe heard about this cryptid.
Big, mostly black, cats were seen in some places where no members of the genus Panthera are native.
Especially Great Britain and Australia are known for their Lithgow panther or the Queensland tiger.
The species I'm speaking about is not a run away panther, they are normal feral cats.
Ok, not totaly normal.
Maybe it's time for a bit history. The shapeshifting ability can be found at every group of tetrapods, but especially the mammels have/had many shifters in their ranks. One of them is a scottish subspecies of the wildcat. When this species were crossed with the African wildcat a new, stronger breed was born.
The alternative form of this breed was much bigger than that of the scottish wildcat.
Fast, the breed become the favorite pet of vampires, werewolfs and so on...
And australia was one of the countries where many specimens were exported to.
Today there is a small wild population of this cats and we can't hide every animal or destroy every camera with pics on it