The mystery of the walnut shell

I'm a mystery writer. My novel Murder in Paris is out officially tomorrow, although Amazon is already shipping.

The mystery of the walnut shell will not be a novel, but it did spark my curiosity that it should be sitting in the middle of the driveway.

There are no walnut trees around. There have been no walnuts eaten in the house recently and as lazy people we are usually willing to pay a bit more to get them preshelled.

We haven't seen any squirrels lately, although there was an adorable red one hanging around earlier in the spring. In previous years, Munchkin, the queen of the kitty hunters, tended to discourage the squirrels from visiting.

Where did it come from?

Who knows...