Sounds more like a cat to me.

Snapping turtles are notorious for de-limbing toads. Toads taste bad (skin secretions) the turtles tend to leave them rather than eat them entirely. Something I witnessed as a kid growing up on a backwoods creek

My cats never mess with toads/frogs. Anoles and skinks, yes, but not toads/frogs.

"This morning I found a toad with three of his limbs bitten off."

Its called nature....things are harsh in nature. Food chain. And of course you should try to not visit certain countries where humans thy cut off all four frog legs for food and leave rest of it to die.

http://www.swissinfo.ch/eng/swiss_news/Is_frog_delicacy_on_its_last_legs.html?cid=1301504