‘There has never been an authenticated case of an unprovoked wolf attacking an adult human being,’ said Carrot. They were both huddling under his cloak.
And after a while Gaspode said, ‘An’ that’s good, is it?’
‘What do you mean?’
‘We-ell, o’course us dogs only has little brains, but it seems to me that what you just said was pretty much the same as sayin’ “no unprovokin’adult human bein’ has ever returned to tell the tale,” right? I mean, your wolf has just got to make sure they kill people in quiet places where no one’ll ever know, yes?’

Substitute Orca for Wolf and you get the same conclusion. If an orca wanted to kill a human, then the remaining evidence would be non existent. If they kill and eat leopard seals and great white sharks, I doubt they would have much problem doing the same to a human.