“No, ma’am.”

“Is it correct that Jamal Griggs had a homicide conviction?”

“Yes, he did. But because he had been a juvenile offender at the time of the murder, his DNA was not included in the databank.”

“Do you know the facts of that case?”

“Yeah. I do.” Mike paused and stared directly at Griggs. “Jamal was fourteen years old. He had dropped out of school to sell drugs with his big brother, Wesley.”

Eli Fine pushed his chair back but seemed uncertain about whether he should be objecting to this line of questioning.

“The girl he killed was sixteen,” Mike went on. “Jamal stabbed her in the back when she made the mistake of accidentally busting up a drug sale by knocking on the wrong door.”

“Did there come a time when you asked Dr. Prinzer for a comparison to be made to Mr. Griggs’s DNA?”

Mike shifted in his seat and ran his fingers through his hair. “Yeah, about three months ago, just after his robbery conviction.”

“Would you tell the court what result you were given?”

“Objection, Your Honor.”

“On your feet, Mr. Fine,” Moffett said. “That’s the only way I can overrule you. What grounds?”

“Hearsay.”

“You’re not offering this for the truth of it, are you, Alex? Dr. Prinzer’s going to testify, too, isn’t she?” Moffett asked, without waiting for my answers. “Overruled. It’s just a hearing, young man. You got no jury. Save your energy for cross-examination.”

Fine sat down and scribbled furiously on his legal pad while Mike answered the question. “There was no hit, Ms. Cooper, but Dr. Prinzer told me she had a partial match.”

I finished questioning Mike, establishing that every other means of identifying the perpetrator in Kayesha’s homicide had been unsuccessful. Moffett needed to understand that a kinship search was our only alternative. Fine went nowhere with his brief cross-examination, and Mike stepped down from the stand.

“The People call Dr. Mathilde Prinzer,” I said. She would take the scientific piece of the testimony forward.

It took more than fifteen minutes to list her credentials and establish her unique expertise in this still-evolving field of forensic science. If this case of first impression was to stand up to appellate scrutiny, I wanted the full effect of this brilliant scientist’s body of work.

In addition to her daily routine with the five city prosecutors’ offices and the NYPD, Mattie had been among the OCME heroes of 9/11, working doggedly with her colleagues to identify victims from thousands of tiny fragments of human tissue.

I ran her through a primer of DNA testing, more familiar to Moffett than to Fine, who had a puzzled look on his face throughout the entire direct.

“When you compare a suspect’s DNA profile to a crime scene evidence sample, Doctor, what are the possible outcomes?”

“Traditionally, Ms. Cooper, we have had three results. A match can be declared if you have thirteen loci in common-that is, thirteen places on the chromosome at which the gene for a particular trait resides,” Prinzer said, speaking slowly and looking at Fine as she spoke. “A suspect can also definitively be excluded if genetic differences are observed. The third option has been a finding of ‘inconclusive’ if we don’t have enough information to make a positive determination.”

“Has the scientific community recently accepted a fourth category?”

“Yes. We have begun to develop indirect genetic kinship analyses, using the DNA of biological relatives, in humanitarian mass disasters and for missing person identifications, situations in which we have only small samples of genetic material. We try to compare those to DNA from surviving relatives. In those instances, we’re usually working with partial matches.”

“Can you explain to the court the meaning of the term ‘partial match’?”

Moffett moved his chair closer to Prinzer.

“Certainly. When we look at the thirteen loci needed to declare a match, there are two physical traits charted at every one of them. You see them as peaks on the Avon case lab report Ms. Cooper provided to you,” she said, as Moffett and Fine tried to find the corresponding page. “These peaks-or alleles, as we call them-come in pairs, one from the mother and one from the father.”

Moffett nodded as he listened.

“In a partial match, at each of the thirteen critical loci, the profiles being compared have at least one allele in common.”

“You could see that on this paper?” the judge asked, bending over the bench and holding out his report to Mattie.

“Oh, yes, Your Honor.” She held the report and pointed to a pair of peaks. “Look right there. In our business, those graphics really stand out.”

“And what do they tell you?” I asked.

“In the case of Kayesha Avon, we’ve got high-stringency matches to Jamal Griggs at eleven of the thirteen loci on his sample. So I know I’m not looking at the DNA of the person who contributed the crime scene sample, but in all likelihood I’m staring at the genetic profile of someone closely related to him. Probably Jamal’s full sibling.”

Probably Wesley the Weasel.

“Has the partial-match technique been used to solve any crimes, to your knowledge?”

“Familial searches have been used with great success in the United Kingdom and Wales,” Prinzer said, citing the cases of child predator Jeffrey Gafoor, serial murderer Joseph Kappen, and James Lloyd, the notorious shoe fetish rapist of Rotherham. “In this country, in 2005, the process exonerated a North Carolina man who’d been incarcerated for eighteen years and identified the killer who’d left his DNA on cigarette butts at the crime scene.”

“Does the FBI provide information on partial matches, Dr. Prinzer?”

“Not as of this time, Ms. Cooper. My colleagues and I are required to submit a request for the release of the information sought, along with the statistical analysis used to conclude that there may be a potential familial relationship between the suspected perpetrator and the offender.”

“Have you prepared the statistical analysis in the matter of Kayesha Avon?”

“Yes, I have. To begin with, Justice Department figures confirm that fifty-one percent of prison inmates in this country have at least one close relative who has also been incarcerated,” she said. “And in this case, the donor of the crime scene semen shares twenty of the twenty-six alleles with Jamal Griggs.”

“Can you tell us what that means, Dr. Prinzer, with a reasonable degree of scientific certainty?”

“Yes, I can. It means that we’re looking for Jamal’s biological brother. For his full sibling-same mother, same father. I believe that’s whose semen was in Kayesha Avon’s vaginal vault.”

I concluded my questioning and watched as Eli Fine wrangled with Mattie Prinzer. Prosecutors and members of the criminal defense bar took courses in DNA advances every six months to keep current with the technology. The Weasel must have thought his high-priced mouthpiece could bluff his way through opposing the search warrant application, but Fine was in over his head.

Moffett watched Fine struggle for half an hour. Finally the judge stood up and twisted his ring as he began to talk. “Let me help you out here, son.”

“Judge, I’m perfectly capable of-”

“Sit down, Mr. Fine. I’ve got some questions of my own.”

Moffett waited until the young man took his seat next to Griggs. “So, Doc, the FBI releases only perfect matches, am I right?”

“Yes, you are.”

“But in New York -you’re satisfied these partial matches are useful?”

“We’re one of the few states that generates them, along with Virginia and Florida. Many more allow law enforcement agencies from other jurisdictions to go into their databases if probable cause is established. We believe kinship searches have an enormous potential to solve crimes, to increase database hits by more than twenty percent all over the country.”