I hear ya JW.
I'm thinking a Good Ole Fashioned Donkey (the Biblical Donkey) Whoopin!
That is what the lad or lass that did this needs.
As to your thoughts iowabow, that's pretty much what I was thinking.
Crossbow, low draw weight, close range, possibly a CB Pistol.
Either a mostly Innocent youngster taking the cat as a target of opportunity not realizing the damage the shot would inflict on the animal if the bolt connected.
Or a teen with ill intent, shooting a friendly neighborhood cat to inflict pain and death.
-gus