Haven't been on in a bit, so excuse me if this theory has already been discussed. Just ran into an acquaintance who is very credible. Acquaintance was visiting friends/family in Frederick, about one block from the Watts' home, during the week it all happened. Acquaintance informed me that there are details of the case known only by the locals.
In particular, acquaintance told me that SW was very concerned about going home that evening, and purportedly told companion something like: Come look for me (SW) if you don't hear back. Allegedly, the reason SW was concerned about going home that evening was because earlier she had phoned CW and asked to speak with the girls, and CW would not let her speak to the girls. It was supposedly at this point that SW suspected something was wrong, prior to arriving home.
If true, this information supports LE's confident refutation of CW's allegations against SW. This info also supports theories that the girls may have been killed prior to SW arriving home.