Weird Archaeology 101 Pop Quiz: Ancient Shekel in Massachusetts?

Good afternoon class,

We've had a few sessions, so I thought I'd give you a pop quiz.

A builder comes to you and says that during the the reconstruction of a wharf in Manchester, Massachusetts, he found a 2000-year old silver shekel of Tyre (Lebanon) in a hole in the nearby sand. He notes the irony in finding it on Holy Thursday, the day Christians commemorate the Last Supper, which is followed by Judas' betrayal of Jesus, for which he was paid in silver shekels. He takes it to the owner of the property. They take it to a numismatist, who determines it is authentic (dating from 126 BC - 66 AD), that it had been worn, and that there is evidence it had been submerged underwater for some time, though there is no formal paperwork to that effect.

The owner does not claim to know how the coin got there and suggests there are hundreds of possibilities. She has done some research on previous owners of the property, but has not found evidence of coin collectors. She also suggests both that an animal might have dropped it there from somewhere else (including possibly a seagull), or that the Phoenicians might have lost it during trade with Vikings in the area.

If this case was brought to your attention, what would your reaction be? Any suggested methods for the arrival of the coin? Possible courses of action?