Crime Scene Procedures

The discoveries, inventions, and theories of our forensic science fore bearers have all culminated into what we know today as the criminal investigation. Often, that investigation begins upon discovery of a crime scene. The information on criminal investigations, and crime scene procedure, is covered in scores of books. A basic overview of crime scene procedures is covered below.

 

First Responder Priorities:

1. 1. Determine need for medical assistance
2. 2.
   Confirm or pronounce death 
   
3. Conduct a scene walk
   through 
   
4. Take steps to preserve and protect
   area
   
5. Secure and isolate the crime scene
   using ropes or barricades
   
6. Exclude all unauthorized personnel
   from scene
   
7. Determine the lead
   investigator

         Physical evidence can be
rendered useless by people wandering through the area. Every single person has
the potential to destroy valuable evidence. It's the responsibility of the
officer to prohibit access to anyone not directly involved with processing the
site (including fellow officers).

  Evaluation of the Area

• Determine the boundaries of the
  scene 
  
• Establish the perpetrator’s entrance
  and exit 
  
• Initial walk though of the scene to
  determine the strategy for documentation of the entire crime
  scene.

   

                                                  DOCUMENTING THE
SCENE  

                                           Photography/Video  

1. Overall Photos 

• Photographs must be in unaltered condition.
• Overview
  photographs are taken of the entire scene and surrounding areas, including walls
  and points of entry and exit.
  
• The
  purpose is to include as much as possible in one photograph.

• The
  goal is to ensure that each important item is in at least one photo.

• Should be taken before anything is
  disturbed
  
• Photographs of physical evidence:
  should show the position and location relevant to the scene.

• Photographs of the body: should show
  the body's position relative to the scene.

   2.    Mid Range
Photographs

• The
  purpose is to focus attention on a specific object. 
  
• Scales should be used when
  indicated. Without a scale, many photos can't be admitted in court. 
  
• Photos of wounds and bruises should
  be photographed with and without scales. 

   3.     Close up Photographs

• The
  purpose is show a specific aspect of an object up close. 
  
• Photos can show pattern of
  injuries 
  
• Photos showing injuries or weapons
  lying near the body are necessary. 
  
• After the body is removed, close up
  photos should be taken of the area underneath.

         Digital/Video
Photography

• Same principles used in regular
  photography apply. 
  
• Overview shots as well as close ups
  should be taken. 

         SKETCHING THE
SCENE

         Rough Sketches:

• Shows all recovered items of
  physical evidence 
  
• Objects are located by distance
  measurements from two fixed points. 
  
• Distances marked must be accurate.
  All distances are made with a tape measure. 
  
• Each item is assigned a letter or
  number. 
  
• The
  sketch shows a compass heading designating north.

          Finished
Sketches

• Usually prepared with the aide of
  templates 
  
• Usually drawn to scale 
  
• Must contain information contained
  in the rough sketch 

                   NOTES

• Required in court 
  
• Includes a detailed written
  description of the scene 
  
• Identifies the time an item was
  discovered, by whom, how and by whom it was packaged, and the disposition of the
  item. 
  
• Notes are used to refresh memories,
  sometimes years later. 

 

    SEARCHING THE SCENE

 Conducting the search for evidence
is the responsibility of the lead investigator. A thorough search is
imperative and no important evidence should be overlooked. Failure to collect
all pertinent evidence may lead to charges of negligence or
tampering.

           Types of Searches

• Zone Search: A small area or room is
  searched. It's used in homicides, rape, drug and bomb searches. 
  
• Ever Widening
  Circle: The
  searcher starts in the middle of the ring and continues in an ever widening
  circle until the whole area is searched. This is used when only one person is
  available to search. 
  
• Straight Line
  Search: Used
  outdoors for body dump search and after mass disasters. A large number of people
  will stand, shoulder to shoulder, and walk across the area in a straight
  line. 
  
• Strip Search: Used for when only a small number
  of people are available to cover a large outdoor area. With this search, the
  searchers will walk straight and then turn at right angles across the area to be
  covered. Down, across, up, across, down, across, up.... 
  
• Grid Search: This type covers a large area. The
  area is divided into a grid and a search is made of each grid. A second search
  will then be made perpendicular to the first
  search.

  INDOOR
SEARCHES

The search will start at the
immediate area at and around the body and move outward. All areas, including
ceilings, windows, doors, and floors must be examined for evidence. Any item
which may carry trace evidence must be collected. Some examples of areas and
things to be searched for are listed below:

• The
  victim                             
  
• Book cases 
  
• Furniture 
  
• Stoves 
  
• Doors 
  
• Windows 
  
• Papers, magazines, and
  mail 
  
• Ashtrays 
  
• Lighting 
  
• Kitchen - Check for place settings
  at table, number of place settings, food present and condition of
  food. 
  
• Heating Conditions - check type;
  vented or unvented; thermostat setting. 
  
• Wastebaskets and trash
  cans 
  
• Bathrooms 
  
• Clocks and watches 
  
• Stairs, passages, entry and
  exit 
  
• Check for tool marks 
  
• Check for signs of ransacking and
  general disorder 
  
• Check for signs of a
  fight 
  
• Check odor of rooms 
  
• Check for blood, hair, signs of body
  fluids, fingerprints, footprints, etc. 
  
• Check for hiding places for weapons
  behind stoves and bookcases, under beds, up on high furniture, under the
  mattress, etc.

 OUTDOOR
SEARCHES

A large area will be searched,
using personnel with metal detectors and sifters. The search will usually be
completed using the straight line, strip or grid method. Some of the things the
searchers will be looking for are: fingerprints, footprints, tire tracks or
prints, bloodstains, scratches, paint flakes, hair, fibers, etc. Soil samples
are also taken in order to compare traces of mud or soil on the suspect's
clothing later. In some cases, collecting samples of the surrounding vegetation
and insects can also prove useful.

  If a vehicle is suspected in the
commission of a crime, a meticulous search is done all over the vehicle,
including the carriage underneath. Officers will be looking for dents,
scratches, scrapes, paint, hairs, fibers, bits of glass, pieces of clothing,
etc. A special vacuum cleaner is used to catch minute traces of evidence. In
vehicles, soil accumulates under fenders and bodywork. When two vehicles
collide, the soil or mud may be dislodged. By doing a soil comparison, it can
later be determined if a particular vehicle was present at the crime
scene.

 

  COLLECTION OF
EVIDENCE

   The collection of physical
evidence is vital to any crime scene search. The goal of collection is to
maintain the integrity of the evidence. Physical evidence can be anything from
huge items to minute traces of blood, dust, and fibers which can only be
examined in the crime laboratory. Physical evidence must be handled in an exact
manner thus preventing any contamination of the evidence. Blood evidence, for
example, cannot be packaged wet or it will grow mold. The handlers need to try
to prevent any change from taking place from the time the evidence is collected
at the scene until it reaches the laboratory.

 EXAMPLES OF PHYSICAL
EVIDENCE

• Blood, semen, saliva,
  sweat 
  
• Hair 
  
• Fibers 
  
• Documents 
  
• Fingerprints 
  
• Glass 
  
• Paint 
  
• Powder residues 
  
• Plastic and rubber items 
  
• Tool marks 
  
• Wood and metal objects 
  
• Impressions

 PACKAGING OF
EVIDENCE

    Correct packaging techniques are
vital to maintaining the integrity of the evidence. If the evidence is allowed
to become contaminated, damaged or evaporated through mishandling, it becomes
worthless. A primary rule of packaging evidence
is that, whenever possible, the items should be sent to the crime lab intact.
Rather than remove evidence from the object, it's preferable that the entire
object be sent to the laboratory. If evidence must be removed, forceps or swabs
can be utilized. If a swab is used, the swab must be air dried before
packaging.

  Folded papers, labeled envelopes and paper
bags are often supplied and are useful for packaging evidence such as hair,
blood and other body fluids, and debris. Ordinary manila envelopes should not be
used, since tiny particles can leak out. Each distinct item must be packaged in
separate paper bags to avoid cross
contamination.

Wet evidence, such as blood, semen,
and saliva, must be air dried first. Any wet evidence can grow mold which
can cause the evidence to deteriorate. Once dried, the evidence can be sealed in
an envelope, then packaged in a paper bag, sealed and marked accordingly. All
items of clothing must be air dried then placed in separate paper bags. Other
containers which can be used include: screw top glass vials, plastic pill
bottles, cardboard boxes, and metal paint cans. Some examples are given
below:

• Arson Material - metal paint
  can 
  
• Blood, Semen, and Saliva (dried) -
  paper bags 
  
• Blood (liquid) - glass
  vial 
  
• Clothing - paper bag 
  
• Fingernail Scrapings - envelope,
  then paper bag 
  
• Bullets - cardboard box 
  
• Fibers - envelope, then paper
  bag 
  
• Drugs - plastic bag 
  
• Paint - metal box 
  
• Soil - paper
  bag

    CHAIN OF
CUSTODY

 A continuous chain of
custody must be maintained in order for evidenceto be accepted in court.
Standards require that every person who handles the evidence must be accounted
for. A log is created, for every piece of evidence, from the beginning of the
crime scene investigation until the evidence is released to the crime
laboratory. This includes the name, date, description, and location of the item,
as well as the handler's name and title.

   Once in the laboratory, the
forensic examiner's signature, the incoming and examination dates, the times,
and the department are also logged in. In order to avoid confusion or
questionable handling, the evidence should be handled as minimally as
possible.

      DISBURSEMENT OF THE
BODY

 The following Death Investigation Guidelines, from the
Department of Justice, are used for disbursement of the
remains: 

• Maintain integrity of evidence on
  the body
  
• Ensure the body is protected from
  further trauma or contamination.
  
• Wrap hands and feet in paper
  bags
  
• Establish victim's
  identification
  
• Participate in scene
  debriefing
  
• Notification of appropriate agencies
  
  
• Notification of next of kin *
  
  
• Inventory and secure property,
  clothing, and personal effects that are on the body. Remove in a controlled
  environment with a witness present.
  
• Blood and/or vitreous samples are
  recovered prior to release of remains.
  
• Ensure the labeling, packaging, and
  removal of the remains.
  
• Secure transportation of the
  remains.