Scene of the Crime by Anne Wingate

rationale for that assertion), and I made several nonsuspect idents from palm prints. (That, also, is impossible, according to the FBI, though their rationale on that one is clearer: Their files are too large to permit manual searching.) I cleared one robbery case—on a fingerprint I had memorized—a year to the day after the robbery took place.
    What Holds Fingerprints?
    This cannot possibly be all, but here are some things I know of that hold fingerprints: aluminum windowscreen frames, paper of all kinds, painted surfaces, unpainted wooden surfaces, live plants, tomatoes, Band-Aids, glass, copper pipe, human skin (if you're fast enough), galvanized metal, firearms, ejected brass from an automatic, shells left inside a revolver, automobile bodies, plastic, and the insides of rubber gloves left at the scene. With very thin gloves and hands with pronounced friction ridges, the prints may be left even through the gloves, a fact that badly confuses the perp when he finds himself arrested on fingerprint evidence after using gloves. There are some things you cannot get prints from: most undressed wooden surfaces (unless they're extremely smooth and previously unhandled), bricks, most rocks and stone, most cloth, most extremely dusty surfaces (although there is a new electrostatic process that makes lifting of prints made in dust possible, it is comparatively expensive and out of the financial reach of smaller departments).
    In defense of my fellow identification technicians, I must hastily add that it is impossible to be able to count on always getting prints from any surface. There are too many variables, including the heat and humidity of the surrounding air, the cleanliness of the surface, and the condition of the hands of the person who left the prints. So for fictional purposes, you decide whether you want prints to have been left in this case or not.
    How Long Do Fingerprints Last?
    Again, there are many variables. On a hard surface, in cold, dry weather, the print may be gone almost instantly. On the same surface, in warm, humid weather, the print may last for weeks if it is undisturbed. On absorbent surfaces such as unglazed paper, the print is almost certainly there permanently; in an experiment, scientists using ninhydrin were able to locate the scribe's fingerprints on an ancient Egyptian papyrus.
    And for an absolutely terrific scene of fingerprinting—definitely the best I ever saw in fiction—read Martin Cruz Smith's Gorky Park, the scene where detectives fingerprint the workshop that was making the fake antiques.
    Fingerprints and the Jackson Street Corpse
    Now let's get back to the Jackson Street Corpse. You still don't know who he is. And once again, you're Detective N.E. Boddy.
    You've already taken care of the evidence outside the house, what little there was, because there was so little that once the photographs and measurements were made and the corpse was removed, there was nothing left to do outside. You've already taken the photographs and measurements inside. Now it's time to get to work with fingerprint powder and evidence bags.
    Chain of Custody
    Figure 4-1 is an evidence tag. All the information on it is absolutely critical; the last two-thirds of the tag consists of what is called the chain of custody. (You may remember that I mentioned chain of custody in chapter three, in reference to the Sacco-Vanzetti case.)
    Without a complete chain of custody detailing in whose custody the evidence was at all times between the time it was collected and the time it was presented in court, the evidence becomes inadmissible - as it should. Although even a proper chain of custody does not

    totally prevent anyone from tampering with the evidence, it at least makes it possible to begin to find out who did the deed if evidence has been tampered with.
    If the evidence is small enough to put in a bag, you'll use a special bag (either paper or plastic) that has an evidence tag printed on it. If the evidence is too