Reporter Robert Kolker examines the troubled lives and lurid ends of a quintet of call girls—possibly the victims of a serial killer (or killers)—in Lost Girls: An Unsolved American Mystery.

How did you find this story?

I first learned about the Long Island serial killer case in December 2010, when the first reports surfaced of the discovery of four skeletons, wrapped in burlap. When the police said they suspected the four victims were escorts, I figured the police would find the killer quickly. But then spring came around and the police still seemed without any leads—and then they found more bodies, and the story became something bigger and stranger than anyone imagined.

Did your emphasis shift as you continued to investigate it?

In the beginning, I hadn’t thought much about the victims. As I kept reporting and got to know the victims’ families, I became struck by how all the attention was on the crimes and the killer, and the victims were being overlooked. To me, the reason for this was obvious and unjust. If they had been fresh-faced middle-class girls, like the ones killed in the late 1970s by David Berkowitz, aka the “Son of Sam,” all of New York would have been in lockdown. But because they were prostitutes who advertised on Craigslist, they were considered almost expendable.

What did you learn about them?

That everything that was commonly assumed about them was wrong. They weren’t outcasts. They stayed in close touch with their families—their mothers and sisters, and, in some cases, boyfriends and children. These weren’t classic cases of human trafficking, either; they weren’t kidnapped or enslaved or held hostage as undocumented immigrants. What they had in common was that they all came from parts of the country the media overlooks—poor, struggling areas where becoming a prostitute might not have been the most desirable path, yet somehow has become a valid, almost normal option. What made the choice to be an escort easier than ever was [Web sites like] Craigslist and Backpage. Prostitutes no longer have to walk the streets or even work with agencies or pimps. The backdrop of an open murder case offered an ideal opportunity to write about the story of five young women’s lives and their families in a way that would make people rethink the mythology and clichés that our culture projects onto prostitution.

Do you think the murders will ever be solved?

Lately, I’ve been reading about more and more serial-killers who aren’t captured or discovered for decades. I would hate to think that would be the case here. Every month or so, there is still a new development or two in the case. Usually, it’s minor, but I keep hoping for a breakthrough.