I know it is long past time for an update, but this will not be a comprehensive update. Instead I will report only one piece of new information:
There has been much speculation about the reason why the extreme LE effort to find the perpetrator of the Delphi Murders case was significantly scaled back. The common theory is that this case is dead cold, and hence LE is scaling it back. However, I have just been informed via an excellent source that that is not correct at all, and in fact, we have much more reason to be optimistic. The reason the case has been dramatically scaled back is because LE feels that they already have a pretty good idea of who did it but they are now focusing on trying to prove their case their main POI. I have no idea who this POI is. Source: Source close to federal LE, US Justice Department.