Back during the Scott Peterson trial and when the CourtTV Message boards were alive, I believe someone who posted on that board (
or it could have been this board as well) took a trip to the Peterson residence, took some photos, posted them on the message board. The prosecution used those photos in their case, years after charges were brought against Scott.
With this case, perhaps the 'fame' of the case brought people forward with information or items that they had no idea even were relevant.
All just wild speculation on my part though.