Would you consider going after two victims part of the MO or part of the signature? I think I can see arguments either way.
I agree. We can definitely identify some from each side. And some of them may overlap a little.
From the MO side, we have the
type of weapon used, such as knife, blunt object, or gun. I am fairly certain we all agree some type of weapon
was used to gain control and possibly commit the murders. I struggle to believe he used his hands directly on the girls, for fear of DNA transfer. Unless, of course, he used gloves. The
time of day that the offender chose to commit the crime may also be a part of his MO. We know that it was unusual for the girls to be there on that day at that time. But only because there was no school. The question is; did he already know this?
From the signature side we have the
specific location chosen to commit the crime. Specifically (IMO), trapping them at the end of the bridge, and leading (or forcing) them to the crime scene. For those of us who believe a weapon was used at some point, it most likely was a
specific weapon chosen to commit the crime. We also have the
specific type of victims he targeted that day. He chose young girls he thought he could control and overpower.
While we don't know what other methods or signatures specific to this perpetrator may have used, we do know he used them. I am definitely in the camp that the girls did not know (or recognize) who BG was. He was counting on that.