I was about to post "Well, duh, of course you kill the shark if you can," but I read the replies first... ho-ley COW.
You don't let any animal that attacks a human {unprovoked} live. Period. I grew up with that rule, as a kid on a farm. Animal attacks a man, it dies.
The sole exceptions would be if the animal was unduly provoked, or if it attacked someone who needed attacking, like a dog biting a tresspasser.
Other than that, you put them down.
Tigers, lions, puma, wolves, coyotes...if it attacks humans, it dies. Why? Because any animal that attacks humans once may do so again.
So there's no proof of sharks being serial human-biters? I don't care. They might be serial humanivores, that's enough to me. Bite a human, get killed.
Why? Because we're the *********ing dominant species on the planet, and everybody else ****ing gets out the way when we come through, that's why.