I think the quote is stringed together:
Several people have reported they think they know someone, who looks like the POI, but can't state specifically a name.
We know there are several people in that group (locals who match the POI, i.e., Native American, male, long pony tail, etc.) and we just need people in that group (the subset of locals who match the POI) we can sort all this out.
I think they really don't think the POI is the shooter, but saw something since he was there so close to the murders.
As was posted earlier, POI has become a non-threatening term that LE uses to coax people in, thinking that the POI might really be the shooter, but will try to throw suspicion elsewhere, but the trained interrogators will make the talk or find inconsistencies or look up other crimes, etc.
Or, they could be convinced that they know the timeline specifically of the murders and witnesses have definitely place the POI to a time and point in the timeline before the girls were murdered and are convinced he can add the missing piece of the puzzle.