“Certain subpopulations will have DNA that is more similar than others, thus increasing the chances of a match. True?”
“That’s true.”
“If you consider the genetic differences of the entire world, you can get long statistical odds. But if you limit your comparison to certain sub-populations, the chance of a false positive is much greater, right?”
Regan took a deep breath. “That’s true. But there’s no evidence—”
“One example of such a subpopulation would be the black race, wouldn’t it?”
“Yes.”
All eyes darted to Wallace Barrett.
“Another would be members of the same family.”
“That’s also true.”
“Among these groups, the chances of a false DNA match are much greater, correct?”
“I can’t deny it.”
Ben smiled. “We appreciate your honesty.” He walked back to counsel table and retrieved an exhibit Christina had found for him a few days before, careful to keep it hidden from the witness. “Dr. Regan, would you say your business has been a success?”
He folded his hands across his lap. “I like to think so.”
“Get a lot of business?”
“Yes, our clients seem to be very pleased with our work—regardless of the result,” he added hastily.
“I’m sure. Just how much business do you have?”
“We’re now processing over six hundred samples a month.”
“Six hundred a month! By a staff of how many?”
Regan was a bit slower to answer this time. He was beginning to realize where this was going. “There are ten of us in the lab.”
“Wow,” Ben murmured. “Ten people handling six hundred samples every twenty or so working days. Must get very hectic.”
“Nothing we can’t handle.”
“Confusing, too. All those different samples flying about.”
“I assure you our labeling protocols are very reliable.”
“Still, Doctor, with all those different samples rushing through the lab— some mistakes must occur.”
Regan ruffled a bit. “Not that I’m aware of.”
Ben looked at him sternly. “Doctor, isn’t it a fact of forensic life that every lab has an error rate?”
“Most government-affiliated forensic labs handle a much higher volume of samples. At our lab, we can pick and choose what to handle. We don’t let ourselves get swamped. Each sample is handled individually and is read by two different analysts for confirmation.”
“Still, Doctor—”
“I assure you, counsel, we are quite careful.”
“Perhaps so, Doctor—but you’re not perfect, are you?”
“I beg your pardon?”
Not really a fair question, but it would get him where he wanted to go. “My mother always told me that no one was perfect, but I don’t know, maybe she was wrong. Are you perfect, Doctor?”
He gazed at Ben wearily. “No, I would not say that I was perfect. Although—”
“You do occasionally make mistakes.”
“I suppose. But even if I erred in the lab, the confirmation procedure—”
“No confirmation procedure is flawless, is it, Doctor?”
He stuttered a bit. “I suppose I could conceive of a situation—”
“And every lab has an error rate, right?”
“If indeed we have an error rate, it would be negligible. Barely worth mentioning.”
“But you did mention it, didn’t you, Doctor?” Ben held up his exhibit, a magazine-size color brochure. “This is the Cellmark annual report, isn’t it?”
Regan’s eyes widened. “It … seems to be.”
“Being a publicly held corporation, you have to file these things, don’t you?”
“I’m … not really sure of the legalities.”
“You’d be committing a securities violation if you didn’t, right?”
“Right.”
“And the SEC demands scrupulous honesty in these things, doesn’t it?”
He folded his arms. “I’m sure you know more about that than I do.”
“Well, Doctor, according to this report, your lab has an error rate of about two percent. Right?”
“If that’s what it says, then that’s what it says.”
“Well, that’s what it says. Is it true?”
There was a long pause before Regan finally answered. “I suppose it must be.”
“Thank you. Now, as this report points out, two percent is quite low, and you should be commended for your high standards of excellence. But the fact remains—two percent is two percent. Right?”
Regan pursed his lips. “Yes, two percent is two percent. I can’t argue with that.”
“So it is in fact possible that your lab made an error when analyzing the Barrett DNA samples, right?”
“It is theoretically possible.”
“Because, in fact, no one is perfect. Not even DNA analysts.”
“That’s correct, counsel. No one is perfect.”
Ben beamed. “Well, my mother will be pleased to learn that she was right after all. So, Doctor, if we may, let’s summarize what we’ve learned. First of all, despite what the prosecution would have this jury believe, DNA analysis is not a perfect science, at least not yet, is it?”
“N-no, it isn’t perfect.”
“What’s more, the chances of making a false identification using DNA analysis are in fact much greater than you first suggested, right?”
“Arguably.”
“And besides which, none of these results are valid if the samples provided are tainted or handled improperly.”
“That’s certainly true.”
“Thank you, sir.” He closed his notebook. “I have no more questions.”
Chapter 53
THREE FOR THREE, BEN kept muttering to himself on his way back to his table. Three witnesses up, three witnesses down, and each time he thought he’d managed to do a reasonably effective job of undermining their testimony on cross. True, he couldn’t totally undo what they had to say—some of that forensic testimony was still keenly damning. But he had managed to do what every defense attorney hopes to do during the prosecution’s case. Sow the seeds of reasonable doubt.
The next witness up to bat was the medical examiner, Dr. Hikaru Koregai. Ben had crossed him several times before, so he knew what to expect. Koregai was gruff, self-important, and most of all, a team player. He was on the prosecution’s side, and he never forgot that.
Koregai took the stand in his usual dignified, deliberate manner. Ben thought he detected some uncertainty in his gait, a barely visible trembling in his step. He had heard that Koregai was having some heart problems.
After the introductions and the credentials—Koregai’s thousands of autopsies, his numerous articles for medical journals—were out of the way, Bullock asked the witness about the present case. “Did you perform the autopsies on the Barrett family members?”
“Yes.” As always, Koregai’s answers were crisp and direct. “I performed the autopsies on the mother, Caroline Barrett, as well as her two small children, Alysha and Annabelle Barrett.”
Ben saw several members of the jury wincing. It was gruesome just to think about autopsies being performed on those two tiny, beautiful girls. He hoped to God Bullock wouldn’t be dragging out any pictures.
“Let’s begin with the children,” Bullock said. His expression was grim and humorless, as befitted the topic at hand. “Based on your examinations, can you identify the cause of death?”
Koregai nodded. “Both children died as a result of an attack by a sharp instrument, probably a knife.”
“And what was the cause of Caroline Barrett’s death?”
“She was also injured by wounds inflicted by a sharp instrument, probably a knife, and probably the same knife that killed her daughters. But she suffered numerous wounds, over twenty by my count.”
There was an audible gasp from the jury box and the gallery.