Has anyone explored the angle of the realtor who found the handkerchief? For me, the obvious conclusion is that the gang had rented a house on Martha's Vineyard and the realtor went to check on the house after they had left. But while that conclusion is somewhat plausible in the context of the entire email exchange, it's also a little weird in context.

The discussion talks about a bunch of other houses the realtor drove them to, as if they were looking for something to rent and had not yet chosen; had they rented one house on this trip but wanted something different on the next? The realtor also suggests they left behind pillows they had bought.

It's a long shot, but might there be public records showing who rented what house and when? Dates correlated against any reported incidents involving children would be an angle to explore.

What is the Sandler Foundation? (The domain Susan/Herbert Sandler used to email Podesta about the handkerchief)

https://wikileaks.org/podesta-emails/emailid/23561