I don't know how solid Neil's alibi is, but if that paint were somehow to match, it seems they likely have the wrong DW.
We know Neil was into the porn and Neil had full access to the MH that night as well. Ol' Keith certainly wouldn't likely have heard anything out at the MH and Neil could have been there and already dumped Danielle back at Dehesa, by the time DW ever left to pick the MH up later that morning.
Pure speculation, but the blue paint may hold the key.