This is a small town. Anyone these two girls knew on any level would also be known by either family or friends. I believe that if someone who knows BG saw the pic and heard the voice, they would be able say, i.e "that's Joe who works at the gas station". And if he was known to the girls only via social media, I think he would have been traced that way by now, considering all of the specialized LE called in to work the case. So for me, he was not known to them and was probably not local to Delphi. But he could be from another town not far away, but far enough so that people who DO know him did not think of him when and if they saw the image.
Jmo