 
Crime Scene Basics
By
Captain Chuck Mantkus
NRLO Director of
Training
First in a series of "Basic Education" for Reserve Law
Enforcement Officers
Sooner or later during your tour of duty, you will
more than likely be involved in a "Crime Scene." You may be
asked to keep the scene secure or even to help in the
investigation. Knowing the basic workings and procedures will
give you the knowledge and background necessary to
fulfill your assigned duties with a feeling of confidence and
self-assurance.
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PRELIMINARY INVESTIGATION
Defined: A
preliminary investigation is a systematic, methodical, observation
of inquiry into allegations, circumstances, incidents, or
relationships for the purpose of obtaining factual
information.
Objectives: Following are the objectives of a preliminary
investigation, together with the ways in which they are accomplished
(the sequence in which these objectives are accomplished may vary
depending on the type of incident and attendant
circumstances).
-
Arrival at the scene: Render first aid and obtain medical help if
needed. This is mentioned first because it is obviously an
Officer's first obligation to check to see if anyone is injured
who may need medical attention.
-
Determination if a crime has actually been
committed: If a
crime has been committed, determine what the crime is.
This objective is usually determined by personal inspection or by
observation or by statements of victims or witnesses.
Whether the matter is civil or criminal in nature, it is usually
obvious at this point and will indicate the next appropriate
action for the Officer to take.
-
Identify the offender:
Investigative activity to
accomplish the objective of identification of an
offender will depend on the circumstances. A victim or
witness may immediately identify and point out the offender
or advise that the perpetrator has just fled the
scene. In other cases, the offender's identity
cannot be immediately determined; requiring interviewing of
victims or witnesses and examination of any physical evidence or
indications in an attempt to make this
determination.
-
Apprehend the offender:
If a suspect is at the scene and
there is reasonable cause to believe a felony has been committed
and there is legal basis for detention, then immediate action is
to be taken. If a suspect has fled and pursuit is not
appropriate, then a prompt broadcast of any identifying
information to Dispatch and to other units would be in
order.
-
Protect the crime scene:
Steps should be taken as early
as possible to secure the crime scene appropriately depending on
the nature of the crime. This would include protection of
potential evidence at the scene from contamination by unauthorized
persons and by the elements. Protecting the scene may be
nothing more than closing a bedroom door, or it may require the
assistance of other Officers or persons to confine an area or to
possibly tape off a larger area, especially if the scene is
outdoors.
-
Summon assistance: Notify other Officers and necessary agencies as soon
as possible regarding appropriate description of suspects,
vehicles, direction of flight, possible destination, etc. As
soon as your needs can be determined, notify your department of
needed personnel, equipment, and of special agencies which should
be notified (e.g., Coroner, photographer,
etc.).
-
Locate and identify witnesses:
Try to locate the person(s) who
discovered or reported the crime, and locate any other witnesses
who may have information. Even hearsay information can be of
value. It is helpful to ask for driver's licenses (keep them
until all witnesses have been identified). It would also be
helpful to keep witnesses separated until their statements have
been taken. A truer picture of happenings can then be
obtained.
-
Officer in charge: You are the "Officer in charge" until one is sent to
the scene. Do everything possible to keep the scene as you
found it. Upon arrival of the "Officer in charge," relay all
information of what you have seen, heard, and of any notes that
have been taken. Be sure to enter the time of all happenings
in your notes.
Crime Scene Notes:
-
Note the
time that the call was received.
-
Make a note of the weather
conditions.
-
Note what other units, if
any, are being dispatched and their potential route.
-
Visualize the area or
neighborhood to which you are responding. This will help you
decide the best approach, which in some cases may make a
difference in your safety and in that of others
responding.
-
Start mentally planning
the likely initial steps or activities routinely required, based
on the information you have.
-
When you arrive, take a
good mental picture of what you see; especially where people are
positioned, and who or what is moving. Check lighting
conditions, parked or moving vehicles, surrounding shrubbery,
buildings, etc.
THE CRIME SCENE
Crime
Scene Definition: The "crime
scene" is the locale within the immediate vicinity of the occurrence
wherein evidence may be found. Obviously, the perimeter of the
crime scene will depend on the type and location of the
crime.
Crime
Scene Notes: Your "crime
scene notes" are of critical importance because they can, among
other things, establish the elements of the crime, reveal the method
of operation, and be used as evidence to connect the suspect(s) to
the crime.
Contents and Format of Notes: Your notes should be brief but clear, precisely
accurate, and recorded at the time of the activity or immediately
thereafter while the item is fresh in your mind. Your notes
should be in chronological order (time sequence) and should be
restricted to important facts. Remember, your notes may be used in
court and are subject to scrutiny by the prosecution and by the
defense.
Types of
Note Information: The following
types of information should be recorded:
-
Initial
Call: Your notes should indicate
the time and date you were initially called, the site or address,
and the nature of the crime or incident reported to
you.
-
Arrival
at Scene: Indicate your exact time
of arrival with a brief description of your observations at that
time. Note whether or not any Officers or Units were present
and what your first activities were. Call paramedics if
needed, etc.
-
Securing
Crime Scene: Indicate the initial
crime scene perimeter, the methods used to secure the scene, and
the names of any Officers or citizens who assisted
you.
-
Victim(s) Identification: Provide appropriate details regarding any victim(s)
including name, age, sex, race, physical description, address,
phone numbers, extent of victim's injuries, etc. Also give
details of the disposition of the victim.
-
Suspect(s) Identification: To the extent known, record all of the same
information on possible suspect(s) as you did on the
victim(s). Indicate any and all persons
held.
-
Witnesses: Get all necessary information (minimally name,
address, place of employment, and home and business phone numbers)
on all witnesses, and record where and when they can later be
reached. Briefly describe what each witness observed or to
what each can testify.
-
Crime Scene Walk-through:
The purpose of the crime scene
walk-through procedure is to:
-
Visualize what the scene looked like before the
crime.
-
Estimate what took place during the
crime.
-
Identify potential evidence, especially if
perishable.
-
You should indicate the time of the
walk-through, the point of entry (if appropriate and known), and
a notation regarding any items which appear to be out of
place or out of the ordinary.
-
Personnel Arrival and Departure:
Note the time that anyone
(including the Officers, the Coroner, laboratory personnel;
photographer, supervisors, or witnesses) arrived and
left.
-
Crime Scene Sketch: Note whether or not a sketch was made and list the
names of any Officers involved in taking measurements,
etc.
-
Photographs: The same information as needed for "crime scene
sketch" above should be recorded.
-
Evidence Collected: Each item of evidence collected must be described
and recorded. Your notes should include:
-
Where it was
found
-
Who was
present
-
Measurements
taken
-
Serial numbers (if
applicable)
-
Any identification marks
or numbers placed on the evidence or "evidence
containers"
-
The disposition of any
evidence collected
EVIDENCE
Identification - Collection
- Preservation
Value of Physical Evidence: Nothing is more convincing to a court or jury than
physical evidence (a murder weapon, a tool mark, etc.) which
inescapably ties a suspect to the scene of the crime. Eye witnesses
can be mistaken, or they can weaken in their positive
identification, or they can become unavailable to trial for many
reasons. These typical problems are nonexistent with physical
evidence which has been properly located,
collected, marked, and preserved. The proper locating,
collecting, handling, and preservation of evidence will many
times be the sole determining factor in establishing the "guilt or
innocence" of the accused.
General Considerations:
When collecting, marking, packaging,
and preserving physical evidence, the Officer must anticipate the
needs of the criminologists who will examine the evidence and of the
court or jury which will consider its impact. The court will
require that the collected evidence and sample materials are
available and that each item is physically separated so that
"contamination" could not have possibly occurred.
Outdoors Crime Scene: As soon as emergency or other urgent considerations
have been disposed of, the Officer should next consider protection
of evidence from bad weather. Tarpaulin, plastic sheets, and
even boxes should be deployed for this purpose. Even if the
weather is not threatening, such protection may be appropriate to
protect the crime scene.
Collection of Evidence: Once an item is recognized for its evidential value,
collection becomes a relatively simple matter of performing the
following tasks:
-
Taking and
handling the evidence with care
-
Marking the
evidence for later recognition
-
Packaging
the evidence to prevent alteration or damage
-
Tagging the
evidence for package recognition
-
Maintaining
the "chain of custody"
Care in Taking and Handling Samples:
Before collecting a sample, make sure
that in doing so other evidence is not destroyed. This can
happen.
Marking Evidence: The purpose of marking an individual item of
evidence is so you can later identify it, perhaps months later
(even if it is not in its original package). In addition to
your identification mark (initials) on the specific item of
evidence, it should be clearly identified in your "sketches,"
"notes," and "photographs" indicating the date, case number, and
where and when it was found.
Packaging Evidence: The reason for packaging evidence is to isolate and
protect it from deliberate or accidental contamination which, of
course, could destroy its value as evidence.
-
Plastic
Bags: While plastic bags have the advantage of
being transparent and air tight, they do not have universal
acceptance because they can cause moist items to mold.
Additionally, unless sealed properly, they can be opened and
resealed without detection; and because of static electricity,
they may not be suitable for some small items such as hair,
fibers, and small paint chips.
-
Pill Boxes,
Glass and Plastic Vials: These types of
containers (especially with screw cap tops) are excellent for
packaging small, loose items such as bullets, casings, paint
chips, fibers, hair, glass fragments, etc.
-
Paper
Bags: Plain, paper bags of various sizes are
still the choice of many criminologists and crime scene
technicians - especially for items such as clothes containing
blood or seminal stains and for moist marijuana.
Securing the bag against undetectable tampering; however, is a
problem.
-
Soil
Evidence: Soil and debris are often found
adhering to the shoes of the suspect (a very small amount can
be significant). If soil is present on shoes or
clothing, the item should be carefully packaged, marked for
identification, and submitted as is.
-
Soil
Samples: Soil should be collected close to the
area where the suspected soil originated. Approximately
two tablespoons are usually adequate. The exact location
from which samples were taken should be included in your
"notes" and "sketches." Evidence soil such as that found
on shoes must be kept isolated from soil taken for comparison
purposes.
-
Liquid
Evidence and Samples: Liquids often occur in
arson or alcohol-related cases. If a liquid is not
already in an air-tight container, it should be marked on the
outside of the container along with the other pertinent
information. Be extremely careful with acids and other
caustic fluids.
-
Blood and
Alcohol: Blood, gasoline, alcoholic beverages,
or similar liquid evidence may be collected by using a pipette
(a very slender glass vial) with suction. The vial is
then placed on a sealed container and marked for
identification. When necessary, small blood samples may
be preserved with a clean piece of surgical gauze or with a
non-medicated band aid. After drying, it may be packaged
in a sealed container and marked for
identification.
-
Firearms: Before a firearm is
moved, you should visually inspect it and note such things as
stains, fingerprints, and the position of the slide, bolt,
hammer, and safety. Weapons may be lifted by grasping
any surface that will not take a fingerprint, such as a
knurled grip. An object should never be placed inside
the barrel. Avoid touching areas which appear to be
blood stained. Removing one of the grips and scribing
the metal that is underneath the grip generally best marks the
firearm.
-
Spent
Bullets: Photographs and sketches should record
the position of expended bullets before they are
collected. If imbedded in wood or plaster, cut around
the bullet until it falls free.
-
Marking Spent
Bullets: Projectiles should generally be marked
on their base. You will rarely have room for more than
your initials. If the base is deformed, you may mark the
nose. The sides of a spent bullet should not be marked
because it will destroy the "land and groove" marks which are
needed for comparison purposes. Each bullet should be
placed in a separate vial and protected by clean tissue
paper.
-
Bullet
Casings: "Sketches" and "photographs" must
first record the location where each casing was found.
Spent cartridge casings should be marked just inside their
open end and should be packaged separately in vials and
protected by soft packing.
-
Loaded
Firearms: Generally, one should not book a
loaded weapon into evidence nor should it be submitted to the
laboratory. If circumstances require submitting a loaded
weapon to the laboratory, adequate warning must be
attached to it. Make sure the safety is in the
"safe" position.
-
Ammunition: Ammunition unloaded
from an evidence weapon should be placed in separate
containers which are numbered to correspond to the respective
chambers (revolver) or placed in with the gun from which it
was removed.
-
Minute
Items: Small glass fragments, paint chips,
hair, fibers, etc. (which may be considered fragile) should be
collected by using tweezers or a similar tool. Such
items should be placed in a screw-top vial as mentioned above
in (2).
-
Clothing
Evidence: Clothing from a suspect should be
collected by having the subject stand on a large sheet of
clean paper while removing his/her clothing. After
allowing each piece of clothing to dry, each item should be
packaged in a separate bag, properly marked. The piece
of paper upon which the subject undressed should then be
folded and submitted as a separate item of
evidence.
-
Restricted
Substances: Suspected drugs should be sealed in
glass or plastic screw-top jars or vials. If the
substance found is already in a container (such as a bundle or
balloon) it should be placed as found in another container,
sealed, and marked for identification.
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