That was the truth. She wasn't lying to him; she just wasn't giving her theories a voice. They had a promising suspect in custody. Ruby didn't want to admit she had doubts until there was more evidence to back her up.

“Pearl Helman's brothers keep calling. They want to know when they can bury their sister,” Bellisario said. “The quicker we close this, the sooner we can let people grieve properly.”

Ruby nodded solemnly. She understood the catharsis that came with a funeral nearly as well as she understood the agony of not knowing what happened. She had put loved ones in the ground herself. It was a relief she wanted to give the families.

“I'll be sure to let you know as soon as her body can be released,” Ruby said.

Bellisario nodded, stepping back away from the door.

Family.

They had spoken to so many family members.

Gabe had brought up his brother, killed tragically young. This connection of family had clearly been rattling around in Ruby and Gabe's subconscious, but now it was coming to the surface.

Ruby pulled up her computer, looking up Vanessa De Vries.

The first hit came from Facebook.

Vanessa's mother had taken it upon herself to start up a Justice for Vanessa page. Supportive comments flooded it, all offering their condolences.

The very first photo was an old family photo, Vanessa appearing as a little girl with her family, in their Sunday best. Vanessa sat between two other children, a young toddler and an older child.

Ruby scanned the text beneath it, the plea of a heartbroken mother.

No mother should outlive her children and I've been cursed to see two of my babies taken too soon. 

She was a middle child.

That was it.

Ruby looked at the wall; at all the names of the family members they'd spoken to.

That was the connection. That was the key she needed to look for. Searching for thirteens through the city would be impossible, but this would narrow down her list if she could cross-reference it with the geography of the first three murders.

Ruby used these parameters to run a search, looking for three-child families in the area. Now having three victims, she had a better sense of the area the killer operated in. It didn't sound like a lot of information, but what other directions could Ruby go in?

The FBI database gave her a long list of families. Ruby felt a twinge of disconnect, seeing the lists, the classic image of the nuclear father, mother, and three children. It had been nothing like hers. Maybe it was nothing like the killer's family either. Maybe there was a method to eliminating the nucleus of the family, killing a middle daughter and letting the pain reverberate through siblings and parents.