And it may be just me, but the whole thing seems to be a pretty easy case: The California law regarding lost items is pretty clear. If you think it's stolen, you have to report it.
The website shows a story admitting to buying the prototype for $5000 and showing lots of pictures holding it, disassembling, etc. They know who owned it, and you're not going to pay $5000 for something that you're not completely sure of.