Let me just say that my son-in-law is LE in a city of San Diego County and he has a number of friends who are LE in various cities throughout SD County.
He told me about the "swinging" the second or third day of Danielle's disappearance. It was some time before I heard about Roberts' story. Son-in-law didn't say this is absolute fact, but he did indicate that a fellow LE in the area had told him about it. So FWIW.........Roberts is likely telling the truth about his source.
We don't want to think that LE would want to harm the case before trial by spreading info about the case, but it happens. Much like we don't want to think or believe that these upper middle class parents could indirectly have been a player in their daughter's disappearance by their alleged actions that night.
This post is the closest thing to a secondary source I've seen yet. With the same problem as before, it comes from an internet chat room or forum where anyone can represent themselves to be anything and claim anything.
My 1st point is, very nasty posts have been made repeatedly on many VD threads based on what amounts to internet urban legends with absolutely no verification of any kind. Rumors have repeatedly been asserted as fact.
2nd point is, I have no doubt that LE looked into the "events" of that night very thoroughly, and they moved on, in a different direction. LE has pursued, investigated and arrested a neighbor, not alleged participants in VD alleged "lifestyle". That to me, speaks volumes about the validity and irrelevance of the "swing" angle.