Caroline Polisi

Police back then also knew that a client used a burner phone to contact Amber Costello on the night she disappeared.

Also, that Maureen, Melissa and Megan had also been in contact with burner numbers right before they disappeared.

So in 2012, with the help of the FBI, the task force determined that most of those calls were connected to cell towers inside a small area of Massapequa Park, Long Island.

They called it the box.

Same.

I mean, I was shocked.

I was really initially just stunned by the profile of this guy.

I mean, essentially, he's the monster living among us, right?

He went undetected for years.

They finally were able to put all of those pieces together.

Investigators say Huerman's personal cell phone records show that his phone was in the same area as those burner phones when they were used to contact victims.

They also say that when the burner phones contacted victims, they were often in Massapequa Park, where Heuermann lived, or Midtown Manhattan, where his architectural firm was located.

But there was also DNA evidence.

Police tailed Heuermann and recovered his DNA from a discarded pizza crust in Midtown Manhattan, which was consistent with the DNA profile found on a male hair discovered with Megan Waterman's body.

And from a legal perspective, when you think about investigative techniques, you know, a discarded pizza crust is fair game for law enforcement to use to test for DNA.

Remember, Heurman had never been arrested before, so obviously none of his forensic information was in any database like CODIS, which is the centralized system that combines local, state and national crime labs information.

So they had to get a new sample for this guy.

Well, that's right, Aaron.

I mean, it's just so chilling.

This is where we start to get this picture of a serial killer essentially hidden in plain sight.