Cell phone pings could be how they found Sarah... but if so, then why haven't they found the other 3?? Wouldn't at least 1 of them have had a phone too?
Okay... so why remove the other 3 if you are only interested in the teenage girl?
Shaniya type case: The other 3 leave willingly to avoid the situation being discovered.
Shasta type case: The other 3 are removed so that bodies are not discovered, which would raise the alert level significantly. If 3 bodies and a missing kid are found, that's huge. If a missing family is found, they might be assumed to have left together.
However, if the goal is to reduce alarm, then the blood defeated the point of this anyway. Seems like a lot of work to go to for very little benefit. Maybe to maintain control of Sarah you take the other 3?
No scenario really makes sense with that blood being there. I just don't see any good reason to take all 4 if you only want 1. :waitasec: