I think you are right that they have figured out who the OBG is and it is not him who committed the murders. MOO
I also believe they have identified OBG.
IMO, it’s the only way the change to the NBG sketch would make any sense. LE has stated that the sketches are of two different people, yet they are no longer requesting information regarding OBG. Even if LE received new information that has pointed them in this “new direction”, I believe they would still be looking for OBG as he was on the trails that day and would still be considered an important potential witness even if they no longer considered him a POI.
Pure speculation on my part, but I think OBG had his own reasons for not wanting to be identified. Those reasons could be anything from his own illegal activities to actually witnessing the murders. (IIRC, LE stated to the killer something along the lines of “you made mistakes - there are witnesses”)
Perhaps he was there and was following the girls, but for reasons other than murder.
Once he was identified, I think it’s very possible that not only was he cleared, but very probable that he is the one that provided additional information that has now thrown NBG into the spotlight.
In my attempt to make sense of it all, I believe that the witness that provided the sketch of NBG only 3 days after the murders reported something he/she saw that occurred somewhere other than the trails that day. Far enough from the crime scene that it was discounted as improbable due to the tight time line. (This would also account for LE’s belief that he was able to move around quickly)
OBG gets identified and provides a description of the person he saw on the trails that day, and that description is a near match to the NBG sketch.
MOO and best theory I have at the moment...
On a side note, it really makes me wonder what was witnessed that was relevant enough for LE to take the time to develop the sketch in the first place...?? Something else to ponder