My understanding is that he rented the house next door. The owner is engaged in one of those neighbor feuds with the Palins. When SP found out about this, and that he was writing a book about her (and expecting it to be negative), she said something about how she didn't know what kind of information he'd get by looking into Piper's bedroom, at her little garden, and the family swimming hole. Piper being ... eight or so, I think. That's where the pedophilia slant comes in.
McGinnis said that he wasn't going to bring in lights, cameras, etc., that he wanted to talk to people who'd known SP for years and that they should be glad it was him and not someone who'd have cameras trained on them.
Todd Palin, seemingly, went and talked to JMcG and things got hostile. Then SP was posting things on ... Facebook, I think. JMcG says he's been getting death threats, has asked for police protection, and brought up the Nazi comment as saying this is the kind of thing the Nazis did, intimidating their opponents and threatening them.
Now it seems the Palins have put up a big fence between their house the the neighbor's but, not satisfied with how effective it's going to be, they're talking about having to move out for the duration of JMcG's lease ... three months, I think.