Comins Pond is a municipal beach, no? Perhaps Molly's killer worked for the town in some capacity.
I really do not know what the difference is between a municipal beach and another. My theory for what it is worth is that the killer is most likely some type of single individual who lived by themselves. That person might be unemployed or off from their job at the time, like a teacher.
There is an episode of a show called Dark Minds. Episode is called Blond, Blue-eyed and Gone. The second half details Molly Bish's abduction and murder. The guy makes a good point on the show about not being able to see the pond from the parking lot.
My question is if he was lurking in the woods behind the lifeguard station, could he see the car she arrived in from there? If it was the guy that her mom saw from the day before, I would think he would want to make sure she was gone.
Like most individuals, Molly probably arrived early to start her shift. I get that impression because there was a swimming event at the beach that day for the kids according to shows done about Molly's case. Most events start at a specific time on the hour. So the killer arrived early too?
The Dark Minds show says a woman saw a swath of pine needles were it looked she had been dragged. Was the swath smooth or jagged? Maybe the killer used something to knock her out. That might mean somebody from a hospital.
If there was indeed a white car in the cemetery parked for the abduction and someone did see it, maybe the killer needed a reason to be there. So from the persons of interest in the case, are any of their relatives buried in that cemetery? Where do most of the bodies in the cemetery come from, what area? I know these might be dumb questions, but sometimes in order to get a lead you have to ask questions that might seem off the wall.
That is about all I can think of with this case. After over 15 years, hopefully there will be some type of clue that helps the case get solved.