Without having yet read your link, I will point out that we have very few basements in Cali, let alone tunnels under houses in local neighborhoods. Manhattan Beach is right on the ocean and would be an odd place to put a tunnel, the properties are not on large lots at all.
The FBI had the tunnels mapped out in one of the pages in this report. It’s sad they sat on this info for a very long time. I think we’re slowly going to get the truth about a lot of things the derps hid from us.
CGato