Wow , this is a nutty story. I've heard about the mysterious feet-in-shoes washing up before. But I have never heard that there was a local indiginous tribe that were slavers and cannibals who ritually cut off feet because they found them unpalatable, and there were sever instances in the 19th century of the "foot in a boot" washing ashore because of them. If that's true, and if that culture is revitalizing then the cops know where to look but political correctness is stopping them from doing so.
I find it a bit hard to believe that such a crazy culture existed in North America into the 19th century and they're virtually unheard of. I'd think it would have been in all the dime pulp magazines of the day and the legend carried over 'til now.