Nodding, Mr. Darrow approached Lucius. “Detective Sergeant, in how many legal cases, would you say, has ballistics played an important role?”

“In the United States?” Lucius asked.

“Ah, yes, Detective Sergeant,” Mr. Darrow answered, “for the sake of His Honor’s nervous health, I think we’d better confine our discussion to the United States.” There were a lot of people who wanted to laugh, just then, but nobody did.

Lucius shrugged. “There are some.”

“Can you give me a number?”

“No. I’m afraid I can’t.”

“But all this business about your being able to determine when a gun was fired by the mold and rust on the thing-that’s been used before?”

“Several times. It began with the Moughon case, in 1879. The defendant was exonerated when a gunsmith determined that, because of the mold and rust accumulations in his pistol, the weapon could not have been fired in at least a year and a half. The murder in question had taken place during that time period.”

Mr. Darrow shook his head, wandering over to the jury box. “I don’t know, Detective Sergeant-maybe it’s just me, but-I’ve seen a lot of mold and rust, in my life. Seems pretty amazing that you can date its growth as accurately as if it were a living creature.”

“Molds are living creatures,” Lucius answered, taking the chance to needle Mr. Darrow in spite of his nervousness. “And rust is simply the oxidization of metal, which conforms to known timetables. Once you have the training, it’s not terribly complex.”

“So you say, Detective, so you say. And I guess we have to accept your word on it-for the moment. So-the gun was fired about three years ago, give or take a few months. And one of the bullets was found embedded in the wagon.” Mr. Darrow’s face wrinkled up again. “I don’t mean to sound dense, Detective, but what about that? The matching of the bullet to the gun, I mean? How many cases have been solved using those techniques?”

“Well,” Lucius answered, a bit more uneasily, “gunsmiths having been matching bullets to gun barrels for decades-”

“So it’s an exact science, then?”

“That would depend on what you mean by exact.”

“I mean exact, Detective,” Mr. Darrow said, walking back over to Lucius. “Containing no margin for error.”

Lucius shifted in his seat, and then pulled out a handkerchief to wipe his forehead. “There aren’t many sciences that contain no margin for error.”

“I see,” Mr. Darrow said. “So it isn’t exact. And what about that bullet? Any sign that it was actually involved in the murders?”

“There were traces of blood on it.”

“Any idea what kind of blood?”

Lucius started to sweat even more visibly and wiped his head again. “There-aren’t any tests, as yet, that can distinguish one type of blood from another.”

“Oh.” Doing his level best to look like he was honestly wrestling with the problem, Mr. Darrow moved back to the jury box. “So what you are, in sum, saying, is that we have a gun that was fired about three years ago-by whom we certainly cannot say-and that was found at the bottom of a well behind the Hatches’ house. It may or may not have been the gun that fired a bullet that was found in the Hatches’ wagon-a bullet that may or may not have been involved in the murders. Is that about it, Detective?”

“I wouldn’t characterize it that way,” Lucius said. “The odds are-”

“The odds are high enough to leave room for reasonable doubt, Detective. At least in my mind. But let’s try a question that maybe you can answer a little more precisely: In how many trials have you offered expert ballistic testimony?”

Lucius was obviously taken completely off guard. “How many?”

“It’s a simple question, Detective.”

Glancing down and going at his forehead one more time with the handkerchief, Lucius quietly said, “This is the first.”

“The first?” Mr. Darrow answered, glancing quickly to the witness box, then back at the jury. “You’re jumping into some pretty deep water for your first time swimming, don’t you think?”

Trying to put up a fight, Lucius answered, “I’ve been studying ballistics for many years-”

“Oh, no doubt, no doubt. It’s just that nobody’s thought to ask you for your opinion yet. I wonder why.” Finally taking his eyes from the jurors, Mr. Darrow loped back over to his table. “That’s all, sir.”

Lucius started to get up, but Mr. Darrow raised a hand. “Oh-there is one more thing, Detective Sergeant. You stated during your opening remarks that you’re a member of the New York City Police Department. Would you mind my asking-what’s your current assignment?”

Looking very startled, Lucius leaned back in the witness chair and tried to stall: “My current assignment? I was asked by the assistant district attorney to analyze-”

“I mean for your department,” Mr. Darrow said.

Lucius took a deep breath. “My current assignment is unconnected to this case, and it would be inappropriate-”

“Isn’t it true, Detective,” Mr. Darrow interrupted, his voice rolling in a righteous way, “that you were assigned several weeks ago to investigate Dr. Laszlo Kreizler-specifically, his role in the suicide of one of the children in his care at the Kreizler Institute in New York City?”

The crowd couldn’t keep quiet at that, and as they started to chatter in surprise Mr. Picton bolted out of his chair. “Objection! Your Honor, the state objects most strenuously! What possible bearing can the detective sergeant’s current assignment have on this case?!”

The judge gaveled the galleries back to silence, then grabbed one of his ears and turned to Mr. Darrow. “Counselor, I had hoped that you were leaving the job of insinuation up to the assistant district attorney. What do you mean, sir, by bringing up such an apparently unrelated matter?”

“Your Honor,” Mr. Darrow answered, “I’m afraid I can’t agree with the court’s assessment of this information as unrelated. When the state’s case rests so heavily on the work of one expert, and when that expert’s integrity and competence are the subject of an investigation being conducted by another of the state’s experts-well, Your Honor, the assistant district attorney is not the only man who can spot a remarkable coincidence.”

The judge bashed his gavel down, his eyes getting hot. “Perhaps not, sir-but this court will not tolerate the introduction of coincidences by the defense any more than it will condone similar behavior by the state! If the matters you’re touching on have some direct bearing on this case, then explain it right now, sir.”

Mr. Darrow just held up his hands, taking his turn at playing innocent. “I apologize, Your Honor, if my remarks were inappropriate.”

“Inappropriate and inadmissible,” the judge fired back. “The jury will ignore the defense’s remarks concerning the witness’s current assignment for the New York City Police Department, and those remarks will be stricken from the record.” The warning gavel was lifted once more, toward the defense table. “And don’t try that kind of thing with me again, Mr. Darrow. I will tolerate no mention or exploration of any subject that does not concern this case and this case alone. Now proceed with your questions.”

“I have no further questions, Your Honor,” Mr. Darrow answered, sitting down.

“Mr. Picton?” the judge said. “Do you wish to redirect?”

“If redirection could wipe the jury’s memory clean of aspersions, Your Honor,” Mr. Picton said, “then I would redirect. As it cannot, I will not.”

“Then the detective sergeant is excused,” Judge Brown answered, “and the state may call its next witness.”

“The state,” Mr. Picton announced, “calls Mrs. Louisa Wright.”

There was a small commotion at the back of the room, as Mrs. Wright made her way in through the mahogany doors.