Looks like another serial killer practicing up for the move to humans.
Definite possability. A stupid child-hood thing doesn’t turn into 2 dozen dead mutilated cats without a lot of work and enthusiasiam.
I should be more clear. The stupid child hood thing would be killing 1 or 2 cats, realizing how awful it was and stopping. If this is a person or persons they are clearly having much fun with this just due to the sheer amount of effort they must be expending.