Scene of the Crime (8 page)

Limit the number off evidence collectors:
Designate one, or at most a pair, of officers to collect all evidence. This places responsibility on specific individuals. It will also tend to avoid confusion at some later date as to who recovered specific items and where they were found.*

Photograph the evidence:
Take photographs as necessary prior to moving or securing exhibits.

Use common sense:
Use knowledge, experience and intelligence in collecting evidence. Consider what significance the exhibit may have and what examinations the laboratory may conduct. With this in mind, the trained investigator will normally be able to correctly secure and preserve the exhibits.

Keep accurate records:
Prepare notes or other records as items

*Author's note: This does
not
mean that only one person should
search.
Rather, it means that in the search team, one person should be responsible for
collecting
the finds.

are collected. Record the item, its condition (if appropriate), the exact location relative to a fixed and permanent position, the date, the time, etc.

Mark the exhibits:
Place permanent and distinctive marks directly on the objects collected if this is possible without damaging the evidence.

Mark the containers:
When unable to mark the exhibit itself, such as in the case of stains, hair, paint, etc., place the evidence in a vial or small plastic or paper envelope, then seal and mark the container. Even when the exhibit itself can be marked, it is usually advisable to seal it in some kind of container and place additional identification marks on the container.

Keep the markings brief:
Initials or the name of the officer collecting the evidence is essential. In marking containers, other pertinent data can be included, such as date, location where found, case number and description of the exhibit. Do not include extraneous information or conclusions of the investigator since these might render the label inadmissible as evidence in court.
Use proper containers:

1. Plastic or cellophane envelopes are excellent for small objects that are not organic in nature.

2. Paper envelopes are used for organic evidence (body fluids, biological evidence, etc.).
Note:
Air dry all evidence items before packaging.

Seal all corners adequately if very small or powdery material is enclosed. It is preferable to place the latter in plastic envelopes. Do not use paper envelopes for fiber evidence as the paper itself may contain fibers and thus contaminate the evidence.

3. Vials, pill boxes, capsules and like containers are frequently suitable, depending upon the exhibit and its condition.

4. Garments and large exhibits can be placed in bags or rolled in paper.

You have undoubtedly seen investigators on television collecting a firearm by sticking a pencil or pen down the barrel. This is, to put it very mildly, not SOP—Standard Operating Procedure. (Remember the term. It's as important in police work as it is in the military.) In the first place, this procedure is unsafe; but even more important to criminal investigation, it could damage the inside of the barrel. The lands and grooves inside the barrel are the main—generally the only—way of definitely identifying which firearm fired which slug.

What Is a Firearm?

Let's back up a little. What do we mean when we say firearms? The more common term, of course, is
gun.
(Do not use
gun
to mean
rifle
in the Marine Corps. If you do, you will be required to spend several days walking around reciting to everyone you see an extremely vulgar little rhyme.)

Categories of Firearms

Firearms fall into two major categories,
small arms,
which include all the weapons normally used by civilians or police officers, and
artillery,
which means larger caliber weapons such as cannon and antiaircraft guns. Crimes almost never involve artillery, although a .50-caliber handgun recently invented in Utah may begin to blur the distinction. But for the time being we'll be thinking here of small arms, which include handguns and weapons normally fired from the shoulder.

Handguns

Revolver (although not technically a pistol, a revolver is often referred to colloquially as a pistol)

Semiautomatic pistol (usually referred to as automatic pistol)

Shoulder weapons

Breechblock Rifle Bolt-Action Rifle Lever-Action Rifle Slide-Action Rifle Semiautomatic Rifle Automatic Rifle Shotgun

A few combination weapons exist, the most common being a shotgun-rifle combination called an
over-and-under,
in which a rifle barrel and firing mechanism sits atop a shotgun barrel and firing mechanism. A double-barreled shotgun may be an over-and-under or a
side-by-side,
in which the two barrels are, as the name suggests, side by side.

The smallest readily available handgun, designed for concealment, is the Derringer. This weapon has a very short range and little accuracy. It would be useful only in resisting or making a sneak attack. Think of it as a "lady's weapon" (as opposed to a woman's weapon, which may be anything) or a "gambler's weapon."

Derringers in the classic style have one or two barrels, each with its own chamber and firing mechanism; another variety, the "pepperbox," has four. Derringer-like innovations include one-shot pistols disguised as fountain pens or miniflashlights; a similar item is a one-shot belt buckle fired by abdominal pressure. What it gains in sneakiness it loses in unwieldiness.

Along the same lines are guns, knives, and stilettos disguised as belt buckles, compact cases, letter openers, keys, and just about anything else you want to name. Swords and single-shot rifles are built into umbrellas, canes and briefcases. Watching a few James Bond movies should give you more ideas.

There are some even less common weapons, generally no longer in production, such as the "lemon-squeezer" pistol (so called because it was cocked by squeezing the grips), that I don't intend to cover here. If you're thinking of writing about anything that esoteric, chances are you're into firearms anyway.

Ammunition

All these weapons fire
ammunition.
But at this point, the terminology begins to get a little confused. For the time being, forget about shotguns. We'll get to them later. Right now we're talking about all other small arms. In the military services, normally a single round of ammunition—that is, a single item to be loaded into a firearm—is called a
cartridge
and the portion propelled through the air is called a
bullet;
but in police terminology, normally what the military calls a
cartridge
is a
bullet
and what the military calls a
bullet
is a
slug.
Decide for yourself which terminology is more appropriate for what you're writing. I'll use them interchangeably in this book.

What is ammunition made of?
Whether you want to call it a bullet or a cartridge, it has four main components:

• The casing or shell;

• The propellant (black powder, smokeless powder, nitrocellulose, or whatever);

• The primer (which is hit by the firing pin, ignites with an extremely hot flame, and ignites the propellant);

• The bullet or slug, which may be solid lead or lead jacketed with a thin layer of copper, steel or Teflon. The Teflon-coated bullets, which slip easily through bullet-proof vests and other body armor, are often referred to as
cop-killers.

How does ammunition work?
The rapid ignition (which actually is not quite an explosion) produces:

• A loud report (which can be muted to approximate a cough by a silencer on some but not all weapons);

• A simultaneous muzzle flash (which cannot be eliminated) and forward propulsion of the bullet;

• A mixture of hot gases and gunpowder residue that is propelled back toward the hand of the person holding the gun.

The heat

• Softens the bullet, forcing it to conform to the shape of the inside of the gun barrel.

How is a shotgun shell different?
A shotgun shell is slightly different; instead of a slug, it contains:

• A primer;

• A load of gunpowder;

• Pellets called
shot;

• Wads,
pieces of cardboard or paper packed in the shell between the primer and the powder and between the powder and the shot.

In shotgun shells that are reloaded at home (check a large gun reference book for more about that), the wadding often is punched out of magazine pages. Many years ago in London, a police officer was murdered. At the scene, other officers found a partially burned fragment of the wadding, which came from an identifiable newspaper three years old. The search for the suspect continued for several years, but when a suspect was finally developed, officers located at his home both the pages the wadding was punched out of and additional shells loaded with wadding from those pages. This evidence proved to be the vital link to convicting the culprit. That sounds good to me. There's no reason you can't reuse it in fiction.

Rifling

With the exception of the shotgun, all these weapons have
rifled barrels.
Rifling, which was developed about five hundred years ago, consists of a series of wide spiral
grooves
cut into the gun-barrel. These grooves, by causing the basically cigar-shaped bullet to spiral through the air much the way a properly thrown football does, greatly improve the accuracy of flight; a smooth-bore firearm is extremely inaccurate at distances of over about eighty feet. (Now you know why you never could hit the side of a barn with a BB gun. It's smooth-bore.) The raised spaces between the grooves in the barrel are called
lands.
Because the heated slug conforms to and mirrors the shape of the inside of the barrel, the grooves will show up on the soft lead of the bullet (or slug) as shallow raised areas; the lands show up on the bullet as grooves cut into it. Although theoretically all the rifling on firearms manufactured in the same batch should be identical, actually, even to start with, there are microscopic differences, because the rifling equipment is worn slightly more with each barrel it rifles.

The more the firearm is fired, the more pronounced those differences become, as the inside of the barrel, reacting to the heat and the friction of the lead rushing through it, continues to wear. This means that it is possible to identify the slug that went through any given barrel. In practice, this means that it is usually possible to tell what slug was fired from any given gun. Although barrels in some firearms are interchangeable, rarely does anybody switch them—but a recent novel had a delightful scene in which a professional killer committed a murder and then he immediately disassembled his weapon, dropped the barrel and firing pin overboard into the Pacific Ocean, attached a new barrel and firing pin, and went on about his business.

In general, criminals don't do that. The pros might.

In real life:
This is not to say there has never been a question as to whether a particular barrel was originally on a particular gun. In the still-controversial Sacco-Vanzetti case, there is no doubt that a barrel that is now on one of the revolvers in the case is the one through which the allegedly fatal bullet was fired, and that the revolvers were in the possession of Sacco and Vanzetti when they were arrested. What does remain in question, however, is whether those particular barrels were on those particular revolvers at the time, and whether the bullet that was presented in court was the one that killed either of the men or one that was later substituted. Proper chain of custody would have prevented those questions from arising.