Betcha its a squirrel that's found your garden and wasn't particularly hungry at the time he dug up your bulb.
Its becoming a ritual in my garden for the past 2 seasons; a squirrel comes, digs up 2 or 3 bulbs and drops where my lawn mower finds them.
The first year I thought it was a friendly passerby or maybe a neighbor who wants to rid his garden and knew that I have a rather extensive bulb patch. Then, after I planted them I realized where the bulbs came from. The flowers were exactly what was showing in my garden.
So the only thing that I could come up is I've got a thief of a squirrel who doesn't dig what I put on his dinner plate.

Yes, pun intended.

Lycoris squamigera?