No Mystery. John Bittrolff is the Long Island Serial Killer.
In 2002, there was a CSI episode about "The Blue Paint Killer" who stalked girls on a remote path. I often found out that CSI stories were inspired by real news stories. There is not much hope to find out what real story may have inspired the CSI episode. But it would have happened around the time when it could have also inspired whoever left Valerie Mack on that path in Manorville.
Valerie Mack was not stalked on a path, she was perhaps strangled in a motel room. But the killer did not want you to know she was really a person with tattoos, a hooker from Atlantic City. The killer wanted her to look like she could have been one of the girls who jogged along that path by the highway in Manorville.
I believe the killer had seen females jogging alone on that path. And he wanted to kill them for sport. Or he at least wanted them to know that he could have killed them for sport. Maybe there was some reason he could not actually kill the one he wanted to kill, because he knew her. He was afraid to kill someone he knew. But he still wanted to terrorize her. So he found someone who could pass as her if you cut the head and tattoos off, and put the body on the path where the person he knew would see her. It was intended to say "look, this could be you."
So the killer was someone who was intrigued by the idea of stalking prey on a remote path. John Bittrolff was a hunter, who also had no problem chopping up dead animals. John Bittrolff lived in Manorville and, as a hunter, would have been curious to walk that path. And John Bittrolff had forbidden impulses, so we know he had forbidden impulses toward the girls he would have seen jogging on that path. But we know he couldn't kill a local because he knew them, and John Bittrolff was a local to that path.
So whoever put Valerie Mack on that path had a specific female walker or jogger in mind, as the target of his display. Yes it is weak to quote Hannibal Lecter, but "How do we begin to covet? We begin by coveting what we see every day." That female had to live in Manorville, so the person who made the display for her to see must also live in Manorville, to know of her. The chances that there are two hooker killers in such a small town, is basically zero.
I posted some more analysis on my web page
Profile of the Long Island Serial Killer
More of a psychological approach than a hard evidence approach. Part of my analysis is that the killer liked the physical shapes of females. A carpenter like John Bittrolff takes interest in physical shapes.