There are dismal looks in the jury box with this news, several of the jurors glancing at Talia with certain disappointment. Robert Rath, my alpha factor, is sitting in the back row, dispassionate, studying the witness.

“Officer Johnson, can you explain to the jury exactly how this strand of hair was lodged in the shotgun?”

Harry and I have been waiting for this one. Nelson is working to get around our theory that there is nothing unusual about a strand of hair from the defendant being found on an item which was normally stored in her home.

Johnson starts off on a lecture about firearms. I object on grounds that the witness has not been qualified as an expert in this area. Nelson meets this with a litany of courses taken and credentials earned by the detective, including a stint at Quantico, at the FBI Academy, where Johnson weathered a course in ballistics and firearms. This is good enough for Acosta.

“If we might continue, then,” says Nelson.

Like a broken record Johnson picks up where he left off. “Most breech-opening long guns, including the shotgun found at the scene, have what is called a boxlock, the mechanism that seals the breech when the weapon is ready for firing. There is a small metal strap on the barrel end of the breech that fits tightly into a groove in the stock end of the weapon. When the two pieces are locked in position, the shotgun is ready to be fired. The strand of hair was found in the groove, held by this strap of metal, protruding down into the breech itself.”

Nelson has a microscopic photograph of this, taken with a macro lens before they lifted the hair from the gun. He has Johnson identify this, and it is marked for later introduction.

“In your professional opinion, Officer Johnson, given your experience and training in firearms, is it possible that this strand of hair could have casually found its way into that mechanism, say, when the gun was on a rack, or in a gun case in the victim’s home?”

“No.” Johnson is adamant, instantaneous on this. “For that strand to have become lodged in the firearm as it was, the breech of the weapon would have to be opened, the hair somehow lodged in it, and the breech closed again.”

“As if the gun were being loaded and fired, is that correct?”

“That’s correct.”

The jury is giving Talia harder looks. Rath is still impassive on the top row.

Nelson considers for a moment, exploring every possible avenue of escape.

“Officer Johnson, assuming for purposes of discussion that such a strand of hair had become innocently lodged in this weapon sometime prior to the day that Mr. Potter was killed, is it not likely that when the weapon was opened in order to load it before it was fired in Mr. Potter’s office, the strand of hair would have fallen out and therefore not been found on the weapon when you examined the firearm later?”

“This is possible,” he says. “It would depend on a number of factors, the amount of oil or grease on the weapon that might hold the hair.”

“But in your opinion there is no way this hair could have casually found its way into the weapon?” Nelson goes back to safe ground.

“No.”

“Thank you.”

Nelson has done all the damage he can with this witness. Fearful of asking one question too many, turning the tide, he takes his seat.

I get up, a legal pad in hand, a few dozen questions. Without much pain I get Johnson to repeat his concession, made during the preliminary hearing. He tells the jury that hair, unlike a fingerprint, does not possess a sufficient number of unique individual characteristics to be linked positively to any given individual, or to exclude all other individuals as the possible source.

He concedes that he cannot say with absolute certainty that this sample of hair belonged to Talia.

I cut him off before he can repeat his opinion as to microscopic similarities. He clearly would like to reinforce this with the jury.

“Officer Johnson, can you tell us what kind of condition this strand of hair was in, the one found in the shotgun?”

He looks at me, confused.

“I mean, was it fragmented, was the end split, was it all in one piece?”

“It was in good condition.” He says this as if to assure me that he had a fine specimen to examine, and there is no basis to impugn the quality of evidence here.

“It wasn’t broken or fragmented?”

“No.”

“In fact wouldn’t you say that this strand of hair was in exceptionally good condition given the apparent trauma it had suffered, being caught in the mechanism of this weapon and presumably jerked out?”

“It was in good condition.” He sticks to the original answer, unsure where I’m taking him.

There is, it seems, a cycle of life for hair as there is for humans. Harry and I have been busy researching follicles. As with many things in science, this cycle is classified into stages. In the last, or telogen phase, before hair falls out, it is fully mature and is anchored in the hair follicle only by the club at its root end, like a ball and socket Below this club new anagen hair is already starting to form. When the old hair falls out, new hair begins to replace it, and the cycle starts again, though not for Harry, who says his follicles have shot their wad.

I take Johnson on a verbal tour. He agrees that this little scenario is gospel in the life of a human hair.

“Officer Johnson, can you tell us, did the hair specimen found in the locking mechanism of the shotgun include that portion known as the ‘telogen root’?” This is the club end of the hair.

He asks for the photograph again and studies it. The root is there, big as life.

“It did,” he says.

“This telogen root, was it fully intact?”

“Yes.”

“Isn’t it unusual to find the telogen root of a hair that has presumably been pulled forcibly, as this one was, from the head?”

“It could happen,” he says.

“That’s not my question. I asked you if it was unusual to find the telogen root still attached to a hair which was forcibly pulled from the head?”

“I suppose,” he says. A grudging admission. “Yes.”

“Wouldn’t it be more likely that this root would come out of its own accord, perhaps on a comb or brush as it neared the end of its life cycle, but that a strand of hair that was jerked from the head would more likely be fragmented, broken off?”

He makes a few faces, a mental trip looking for exceptions to this norm.

“Yes,” he says, “that would be usual.”

“Isn’t it more likely that if this hair had in fact been caught in the weapon, and forcibly pulled from the head of Talia Potter, that it would have been fragmented, broken off somewhere above the root?”

“Possible,” he says.

“I’m not asking you if it’s possible; I’m asking you if it is not in fact more likely.”

“I don’t know,” he says. A little evasion.

“Is it not possible, Officer Johnson, that if someone wanted the police, or this jury, to believe that Talia Potter had fired that shotgun on the day that Ben Potter was killed, that person might very well have obtained a hair sample, from a brush or a comb belonging to the defendant, and placed it in the weapon?”

He makes a face like this is pure fantasy.

“Isn’t it possible, Officer Johnson?”

“Possible,” he says.

“From your own testimony, officer, isn’t this theory, that someone might have planted that hair on that gun, isn’t this theory in fact more consistent with the physical evidence discovered at the scene, than the theory advanced by the state, that the hair was caught in the gun and pulled out?”

He stops dead on this. “I don’t understand the question,” he says. Johnson’s looking for signals from Nelson.

I get my body between them.

“Isn’t it more consistent, Officer Johnson, based on this single strand of hair and considering its condition and the presence of the telogen root, to believe that someone might have planted that hair as opposed to having it pulled from the head of the defendant? It’s that simple.”