Gonzo and Cruz turned to find Chief Marshal Jesse Best taking up most of the space in the doorway.

“FDS?” Gonzo asked. “What’s that?”

“Familial DNA Searching,” Best said. “Simply put, it’s when you run the DNA you have through the system to look for close relatives. That can lead you to someone who’s already in prison or has submitted DNA in a previous investigation. From there, you work backward through the person’s male relatives until you find the one you’re looking for.”

“Ah, right,” Gonzo said. “I’ve heard about that.”

“I’ve been reading about it,” Freddie said. “It’s been used in several cases that never would’ve been solved otherwise, but DC and Maryland outlawed the practice.”

“How come?” Jeannie asked.

“Fear of it targeting a disproportionate number of minorities, and the FBI has been slow to embrace it. The NDIS can’t be used for familial searching,” Freddie said, referring to the National DNA Index System.

“How does FDS work?” Jeannie asked. “I haven’t done the research yet.”

“Say for example a perp’s brother is in the system,” Freddie said. “In that case, a familial match on them can lead us to the guy who did our crime, but it’s not without controversy. For instance, say the family doesn’t know that the person whose DNA is in the system had committed a crime. This process would ‘out’ the first person, because we’d have to disclose what led us to the second person.”

“I can see how that could get messy,” Jeannie said.

“Very, or if we target an entire group of siblings, for instance, we put them all through an investigation in the effort to find the guilty one,” Freddie said. “Or maybe we uncover a previously unknown paternity situation.”

“People have raised privacy concerns as well as Fourth and Fourteenth Amendment concerns regarding illegal search and seizure and equal protection,” Best said.

“How so?” Jeannie asked.

“Requesting samples from family members who haven’t committed a crime, for instance, puts their DNA into the system, and again, the disproportionate representation of minorities in CODIS and the many issues associated with that.”

“I see,” she said. “Well, if we have a serial rapist on the loose who’s escalated to murder, we might be able to make a case for an exception to the local law prohibiting the use of FDS.”

“It’s definitely worth considering,” Best said. “Cases like this one are usually the exception to the rule when it comes to new technology. In my experience, when there’s a violent predator likely to strike again and all other investigative options have been exhausted, jurisdictions are willing to consider it, even with laws on the books.”

“That’s true,” Freddie said. “If we can present a strong rationale for the use of the technology in this one isolated case, we might be able to get them to make an exception.”