I don't agree GJ discounted BS when he took over. He has recently downplayed his then interest in BS, mentioning that he was against the raids happening at the time they did and pointing out that he wasn't in charge then. But he oversaw BS's arrest on the other matter and he made a big deal about BS being a suspect in William's disappearance while opposing BS's bail.Yes it does appear that BS was the focus with the previous investigator and information was leaked to the press back then. When Jubelin took over he seems to have discounted BS (although they still seem to have some animosity towards him - perhaps they are suspicious of all police for some reason) but he always refused to discuss POI's to the press so I guess that is why the general public were not aware that the focus had changed. However, now he is off the case it seems focus has changed again.
His method seems to be to personally focus on and pressure one suspect at a time. I don't necessarily think that he or the investigation lost all peripheral vision in doing so.