re: Burglary update - advice needed

More info for clarity -- All three are in jail. All three confessed to between 10-20 burglaries. None admitted to my house, but one says the other two had our jewelry. This particular guy has a non-public defender attorney, so has been a little more chatty. Detective feels there's really no reason to doubt what he says, other than that they are all dumb as frick.

The detective didn't know what canal or when it was thrown, or the talking thug didn't know, depends on how thoroughly he was questioned. I asked detective what canal, and he said "we don't know." I suspect he wasn't asked. (I mean, if you see someone throw something in a canal, how do you not know what canal?)

In investigating these shitheads, I google mapped their address (well, the address of two of them), and low and behold, it backs up to a drainage canal (the planters canal on the westbank of JP - not too worried about anybody potlicking me on this one) and there is an empty lot next to it. so, in my mind if it was thrown in, that's where. stupid frick tossed the most valuable thing he stole in a canal. figures.

I don't think a magnet will work, as it's platinum. The more I think about it, I assume visibility in there is zero. I'm also sure the water is seriously nasty. Seems the only option though is to metal detect and just jump in and look.