The find was startling in itself: that of a massive crocodile head washing around in the surf at St. Lucia, South Africa.

But what really has people concerned is the unanswered question: What kind of creature was powerful enough to decapitate the giant reptile, and is that creature still lurking just off the beach?

Great white shark? Bull shark? Human poachers? Hippopotamus?

These are some of the guesses being made in the days following the discovery by Brigitte Cary-Smith and husband Neale, who found the crocodile head while walking their dogs on the beach near the mouth of the Black Umfolozi River. (Below is video footage shot by the couple.)

The length of the crocodile has been estimated at 10-plus feet.

“It has created a huge amount of interest all over the world and local people have gotten involved and are doing some investigating,” Neale Smith told News 24.

Smith told the Sun that he thinks the croc killer was a shark. He also suggests this in the video commentary.

“It’s quite normal for sharks to swim here in the sea at St. Lucia and it’s also very normal for very large sharks to be very close to the shore.”

Some locals, however, have said the most likely culprit is man. Whatever it may be, swimmers and surfers probably will want to think twice before entering the water any time soon.