re: A few chunks of info are missing
It was discovered April 13, but no suggestion about when it happened. There's an inference that it had just happened, because the site's relatively near their home and you might think that they'd notice right away. But I don't know, I'm just trying to make deductions.
You're right, insufficient info, and it doesn't sound like a concerted effort was made to scientifically investigate. I'm not trying to make a case that something "supernatural" happened there. I'm more interested in seeing if it's possible to come up with an explanation that covers all the information we do have. More of a thought problem than anything else.