I admit that I've skipped a few pages again, so I hope I didn't miss someone saying this. I keep reading about people suspecting that someone recently arrested was also responsible for the deaths of these girls, and that's the change in strategy he mentioned. What I'm wondering is if the arrested person had been a suspect in the past, but it was his "alibi" being spoken to in the PC. Possibly BG was the alibi for someone else (who couldn't prove where he was), and when that person was arrested, he admitted that he hadn't been with "BG" and told them where he really was - possibly doing something else illegal. It's very possible that all, or most, of BG's friends know that he's guilty, but out of fear or loyalty won't testify against him.
I know we aren't supposed to use personal stories, but I can delete this part if necessary. Some of my relatives had a friend who was involved in manufacturing and selling drugs. When one of the partners of that friend was arrested, he thought their friend was the one who had turned him in. His brother and several friends basically kidnapped the guy (held him in bound and usually gagged in his own home) and tortured him for several days before finally murdering him and stuffing all, or most, of his body in a duffle bag. The guilty parties were both males and females between the ages of 16 or 17 and 22 or 23, it's been a while so I don't remember the exact ages. Anyway, for many years the most common response within at least 3 counties when someone suggested talking to the police about someone's illegal activities was, "And end up like R*** P***?, no thanks!"
Ironically, when the group was eventually arrested, one of the murderers admitted that he was the one who had turned the original guy in, but knew if he admitted it to save his friend that it would have been him in the bag instead.