Dead Guilty

hanging.’’
‘‘So,’’ asked Garnett, ‘‘what does that mean?’’ Diane took the rope and tied an overhand knot,
pulling it tight. ‘‘I just decreased the strength of this
rope by fifty percent.’’
‘‘You’re kidding.’’ Garnett spoke in a way that sug
gested all his ropes had knots in them.
‘‘No, and in a worn rope, that’s significant. Chris
Edwards was a husky, athletic young man, and a big
portion of his weight was going to be on that rope
that was barely adequate. It was another bad choice,
like the square knot. The perp didn’t know what he
was doing.’’
‘‘But it didn’t break,’’ said Garnett.
‘‘No, it didn’t, but it was too close to the breaking
point to be a safe choice.’’
‘‘Well, you’ve convinced me about the ropes,’’ said
the sheriff. ‘‘But that still doesn’t tell us if the murders
are connected.’’
‘‘No, it doesn’t,’’ said Diane. ‘‘The evidence we’ve
looked at so far seems to indicate it might have been
a single perp at the Edwards crime scene. But we
don’t yet have any indication from Cobber’s Wood to
point to a single perp or more than one.’’
‘‘Could have been a whole gang of ’em,’’ said the
sheriff. ‘‘And for reasons we don’t know, one of them
might have killed Chris Edwards. It might not be the
same one who did the rope work in Cobber’s Wood.’’ ‘‘But the evidence does give us an MO for the per
son who tied the knots on Chris Edwards,’’ said
Diane. ‘‘He probably always ties knots the same way
because he doesn’t know any other way.’’
‘‘I see what you mean,’’ said the sheriff. ‘‘If we find something all tied up in a suspect’s house, for instance, the way he ties his knots might connect him to one
crime scene or the other.’’
‘‘Yes. It can’t be the only evidence, but...’’ ‘‘But it’ll give us and the suspect something to talk
about in the interrogation room,’’ said the sheriff. ‘‘I have to agree with Chief Garnett,’’ said Diane.
‘‘It’s too big a coincidence that Edwards was killed
just after he and Mayberry discovered the bodies.
Have you found Steven Mayberry yet?’’
‘‘No. Nor have any of his friends or relatives seen
him. Frankly, we don’t know if he’s on the run or if he
met with the same fate as Edwards. Have you found
anything else interesting from the Cobber’s Wood
crime scene?’’
‘‘Orange carpet fibers. Jin’s working on the brand.
We’ll be able to tell you something about the se
quence of events when we’re finished looking at the
tracks and other impression evidence. We also found
brown shed human hair.’’
‘‘Shed hair,’’ said the sheriff. ‘‘So you can’t do any
thing with that. As I understand it, you can’t get DNA
from shed hair—you need the root. Is that right?’’ Jin glanced over at Diane. He raised his chin and
eyebrows so slightly that probably only she and David
noticed. She knew what he was urging her to tell them.
He’d been talking about it ever since he read the arti
cle, and now here was a chance to give it a try. Well,
why not? she thought. The sheriff was apparently en
amored with DNA.
‘‘Tell me what you know about DNA,’’ she asked
the sheriff.
Sheriff Braden shifted in his chair and gave her a
long stare. ‘‘Now, I’ve always heard you can’t get DNA from hair that’s been shed because it doesn’t have the root, and that’s where the DNA is. Are you
saying that’s not true?’’
‘‘It’s not precisely true. Shed hair does have nuclear
DNA, just not much of it. The root of a hair has about
two hundred nanograms of nuclear DNA. The shaft
has less than ten—not enough even for a normal PCR
test. Added to that little difficulty is that the pigments
in the hair can inhibit the PCR reaction.’’
‘‘PCR—that’s the test that copies DNA?’’ said
Garnett.
‘‘Yes,’’ the sheriff answered. ‘‘That’s it.’’
‘‘Polymerase chain reaction,’’ said Diane. ‘‘It’s a
powerful method that can be used on degraded and
small samples of DNA. However, some samples are
just too small.’’
‘‘Like shed hair,’’ said the sheriff.
‘‘Yes,’’ agreed Diane. ‘‘Shed hair does have more
mitochondrial DNA, but that type of DNA doesn’t
have the identifying power that nuclear DNA has. It’s
too heterogeneous and doesn’t have the poly
morphisms.’’
‘‘I can see how that would be a handicap,’’