Forensic Science: Proper Crime Scene Techniques. Essay, Research Paper
The word “Forensic” is derived from the Latin forensus, meaning “of the
forum.”1 In ancient Rome, the forum was where governmental debates were
held, but it was also where trials were held — the court house. From that, forensic
science has come to mean the application of the natural and physical science to
the resolution of matters within a legal context2. Forensic Science can be viewed
as a tripartite structure consisting of 1. Collection: which pertains to the science
investigation, 2. Examination: which pertains to the medical investigation and 3.
Presentation: which pertains to the courts. A forensic case will involve all aspects
of each of the three structured elements, each being as important as the other. It is
obvious that there needs to be a collaborative approach for the successful
completion of each case. Each step in forensic science must be done in an exact
order, therefor it can be assured that the investigation can have few doubts about
what is being debated. In this paper I will focus my attention on the first aspect
of the three step structure, Collections and Scientific Investigation. I will show
what should be done at crimes scenes, how crime scenes should be handled and
what steps must be followed to ensure that all evidence is pure as when the crime
was committed.
The purpose of crime scene investigation is to help establish what
happened at the crime and to identify the responsible person(s). This is done by
carefully documenting the condition at a crime scene and recognizing all relevant
physical evidence. The ability to recognize and properly collect physical evidence
is often times critical to both solving and prosecuting violent crimes. It is no
exaggeration to say that in the majority of cases, the law enforcement officer who
protects and searches a crime scene plays a critical role in determining whether
physical evidence will be used in solving or prosecuting violent crimes. In a
personal interview, Lt. Micheal Hritz of the Edison Township Police Department
explained, “An investigator must not leap to an immediate conclusion as to what
happened based upon limited information, but must generate several different
theories of the crime, keeping the ones that are not eliminated by incoming
information at the scene. The crime scene is the only link between the crime and
its victim, if any or all evidence is destroyed or lost, the crime may never be
solved. It is imparative that the officer know what, how and where to look for
key evidence.”
Documenting and Examining a Crime Scene
Documenting a crime scene and its conditions can include immediately
recording transient details such as lighting, furniture, fingerprints, and other
valuable information. Certain evidence if not collected immediately can easily be
lost, destroyed or tainted. The scope of investigations can also extend to the fact
of argument in such cases as suicide or self defense. It is also important to be
able to recognize what should be present at a crime scene, what to look for at a
crime scene and what might appear out of place. A crime scene often does not
pertain to the immediate area in which a victim or actual crime has occurred, but
the possibility of escape or access routes should also be checked. Anything which
can be used to connect a victim to a suspect or a suspect to a victim or a crime
scene is relevent physical evidence. Richard Saferstein explains, “Physical
evidence encompasses any and all objects that can establish that a crime has been
committed or can provide a link between a crime scene and its victim or a crime
and its perpetrator” (31). I will now explain the proper techniques and ways a
crime scene and physical evidence should be handled and examined.
One of the first things an officer should do once he approaches a crime
scene is to take control and secure the scene as quickly as possible. This is to
prevent anyone from tainting evidence and to keep unauthorized person(s) out of
the area such as the press, the public or anyone who doesn’t belong. While this is
being done, an officer should also be alert for discarded evidence and note if
there are any possible approach or escape routes. After an officer does this, he
should determine the extent in which the scene has been protected and make sure
there is adequate security in the area. All persons entering and exiting the crime
scene should be logged and kept down to a bare minimum to ensure the purity of
the crime scene when the case goes to court. Each person involved in the crime
scene should have knowledge relative to its original conditions to prevent from
accidental movement of objects, evidence or anything which might hurt in the
investigation of the crime. When all of this is done, the next step which can occur
is the actual examination of the crime scene.
The examination of the crime scene will usually begin with a walk through
of the area along the trial of the crime. The trail is that area which all apparent
actions associated with a crime took place. It is also sometimes marked by the
presence of physical evidence, this may include the point of entry, the location of
the crime, areas where a suspect may have cleaned up and the point of exit. The
purpose of the walk through is to note the location of potential evidence and to
mentally outline how the scene will be physically examined. The first place
investigators should look is the ground they walk on. This is to prevent any
evidence from being destroyed and if observed should be marked and warned to
others not to step in that area. As the walk through occurs, the investigators
should make sure their hands are occupied and they don’t touch anything. The
best way to prevent from touching anything is to keep your hands in your
pockets. Once the walk through has been completed, the scene should be
documented with videotape, photographs and sketches. Any or all objects can
provide a link between a crime and its victim/suspect, therefor it is imperative
that the crime scene be well photographed and recorded.
Recording a Crime Scene.
One of the first steps in documenting and recording a crime is videotape.
Videotapes can provide a perspective on the crime scene layout which cannot be
as easily perceived in photographs and sketches. The condition of the scene
should remain unaltered with the exception of markers placed by investigators to
show small things which might not be seen such as bullets, blood stains or other
key pieces of evidence. A key in videotaping is slow movement through out the
scene and should be done so from beginning to end. It is also wise to pan an area
twice in order to prevent unnecessary rewinding of the tape when viewing and to
make sure the taper has captured everything. Taping should begin with the
general outline of the scene and surrounding area. Taping should continue
throughout the scene using different angles, close-ups, and still shots for a few
seconds. Once video taping has concluded it is then best to also capture the crime
scene with still photography.
Regardless if a scene has been videotaped, still photographs are a must at
every crime scene. Although videotaping does record everything, photographs
can demonstrate certain things such as direct comparison. Actual size
photographs can be used to compare fingerprint and shoe prints photographed at
the scene against the suspect. Again, when photographing, the outer part of the
scene should be taking first to show the surrounding areas, then towards the
crime scene itself. Wide angle photos should be used of the crime scene and
surrounding areas. A good technique to use when shooting rooms is to shoot
from many possible angles such as from all four corners, from a doorway or from
a window. When close-ups are required of key pieces of evidence, a ruler should
be photographed with the items where relative size is important. While each
photograph is being taken, a person should also be taking notes on what the
person is shooting, in order at a later date to understand what was trying to be
accomplished. After still photography has be taken, the final step in recording a
crime scene is to sketch and draw the scene out by hand.
The final phase in recording is to sketch the crime scene. While
photographs are two-dimensional and often can distort distance and size,
sketches provide the means of showing distance or objects, and a over-head view
of the area and surroundings. A sketch is usually made of the scene as if one is
looking straight down or straight ahead. Measurements should be taken at crime
scene of distances between two objects, room measurements and key pieces of
evidence. Two measurements should be taken at right angles to each other from
two reference points. Each measurement should be double measured to make
sure they are correct and accurate. A final sketch can be made by a professional
using all the measurements and notes taken by the investigators. However, the
original sketches should not be thrown out but saved along with other key
evidence in case a discrepancy occurs or something was missed. Once the crime
scene has been recorded with videotaping, still photography and sketches,
gathering of evidence can occur.
Searching for and Gathering Evidence at Crime Scenes.
Gathering and locating physical evidence is a very slow a tedious job when
done correctly, however, it can yield many clues. One of the first things an
investigator must determine is the size and area which must be
man focus searched must include all probable points of entry and exits used by
the criminals. When searching, certain patterns may be used to cover and
examine the area. There are about three different ways in which an area can be
examined. One way is a spiral search method. This method is done by starting in
the center of the scene and work in a spiral outward until all of the scene has
been covered and checked. Another method and usually the preferred method is
the grid method. This is done by marking the crime scene into a grid and walking
in a straight line from one side of the grid towards the other where as you make a
180 degree turn and come back a few steps over from where you just searched.
This pattern overlaps itself and I feel is one of the best search methods. The final
method used is a quadrant or zone search. This is when the scene is divided into
certain quadrants, usually four and each zone is searched with either the spiral or
strip line search. Then after each zone is searched, the overall scene can be
searched using the above patterns.
When evidence is found it must be package and protected in a way that
prevents any physical change from happening from the time it is taken to the it
reaches the crime laboratory. Such things like breakage, contamination,
evaporation and tainted samples can all be avoided with proper handling and
packaging. Original conditions must be maintained at all cost and when ever
possible the entire object should be submitted to the crime laboratory. Good
judgment must be maintained and common sense usually plays a role. Each
different item must be placed in separate containers to prevent cross-
contamination. It is also wise to take “comparative samples” so that evidence can
be compared to normal or controlled pieces. Unbreakable bottles with lids are
good for such things as hair, glass, fibers and other evidence. However, when
anything contains blood evidence, it must be placed in a non-sealable container,
i.e. paper bags are the best. This is to prevent bacteria from forming and possibly
making the evidence unusable. Also good for evidence collection are manila
envelopes, cardboard boxes and paper bags. Besides blood, special attention must
be made towards clothing. All clothing must be air dried and place individual in
separate paper bags to ensure constant circulation to prevent mold or mildew
from occurring. The only time a sealable container must be used, is in the cases
when suspicious fires are being investigated and this is to prevent the loss of
petroleum residues.
Finally, with gathering evidence at crime scenes, an investigator must
make sure he not only labels the evidence, but makes an accurate account on all
sketches and diagrams. Evidence should not be handled excessively after
recovery and should be kept down to as few people as possible. Investigators
must constantly check paperwork, packaging notations, and other recording of
information for possible conflict or errors which may cause confusion or
problems at a later time in court. Their are four basic rules which I found out an
investigator should remember at a crime scene; The best search options are
typically the most difficult and time consuming, but yield great results; You
cannot over document physical evidence or the crime scene; There is only one
chance to perform and investigate the crime scene properly; When searching, a
cautious approach should be taken and then a vigorous search for hidden and
concealed areas should be done. After all this has been done and all the physical
evidence has been located and noted, a final survey should take place in case
something has been missed and all notes, measurements and diagrams should be
checked for accuracies.
Once evidence is gathered it must be sent to a laboratory for processing
and further investigation. When items are to be delivered the method usually
depends on how far away the laboratory is from the crime scene. In most cases, a
state or local laboratory is within a few hours and shipment can be made by
personal delivery. However, in some cases when items must be shipped to F.B.I.
headquarters in Washington D.C., personal delivery is usually out of the
question. When an item needs to be shipped via mail, it should be packaged in a
way not to damage it. However, Postal regulations do prohibit such things as
ammunition or explosives from being send through the mail3. Each item when
shipped should be logged and sent with a checklist in order to make sure
everything shipped is accounted for. A detailed report should also be sent of the
crime, notes, and why the item(s) were sent and what should be looked for.
Along with the evidence, control specimens should also be sent to the laboratory
so that they can compare evidence to a normal piece of what is being looked for.
Legal Considerations at the Crime Scene.
One of the main concerns with physical evidence always debated by the
courts is weather or not the evidence was obtained legally. Often with a few
major court cases, evidence has been thrown because it was obtained illegally to
make sure of a conviction. The Fourth Amendment of the U.S. Constitution
states, “The right of the people to be secure in their persons, houses, papers, and
effects, against unreasonable searches and seizures, shall not be violated, and no
warrants shall issue, but upon probable cause, supported by oath or affirmation,
and particularly describing the place to be searched, and the persons or things to
be seized.” With this, the Constitution means the police do have a right to seize
items or evidence which might help them in determining a suspect, however they
do not have to the right to take the items illegality. The police must have probable
cause in order to take property and seize items which belong to someone else.
Unreasonable searches and seizures occur when the officers in charge do not
have the authority to be at a certain place or do not have the courts/owners
permission to look at, around, or about the persons property or area.
One case which clearly shows how illegal searches and seizures took place
against a defendant is in the case of Michigan v. Tyler4. In this case, Loren Tyler
who leased a business was charged with arson after his business was destroyed
by fire. During the investigation, various items and physical evidence were
recovered from the building. However, on three other separate occasions, 4 days,
7 days, and 25 days after the fire, investigators came back to the scene and again
took various items which they thought would help them build a case against
Tyler. Each of these searches were made with out a warrant or without consent of
the owner. During the trial, the physical evidence seized in all four searches was
used to convict Tyler of arson. On appeal, the U.S. Supreme court upheld a
reversal of the conviction saying that the morning search to be proper. However,
because the other searches were made without consent, or with out probable
cause, the subsequent reentries to the scene were inadmissible and new trial was
granted on these circumstances. The message as explained from the Supreme
Court is clear, “When time and circumstances permit, obtain a search warrant
before investigating and retrieving physical evidence at the crime scene”
(Saferstein 50).
In conclusion, as we can see through out this report, collection and
recording of a crime scene is very important, with out proper rules and special
handling, a criminal can go free. The purpose of crime scene investigations is to
help establish what happened, and to identify the responsible person(s) or
victim(s). To figure this out, careful recording and investigations of a crime scene
must take place. Recording the crime scene details such things as place, time,
conditions, lighting, fingerprints, evidence etc. To record a crime scene such
things as videotape, still photography and sketches are used to give a “story” or
“time line” of what happened and what took place. Once the crime scene has
been recorded, actual examination for physical evidence occurs. This is where
the investigators look for clues such as fingerprints, blood stains, items or
anything which might lead them towards a suspect. When gathering evidence,
each item should be place in separate containers and certain rules for blood
stained clothes and fire investigations apply. The investigators must keep tract
and record everything in which they recover from a crime scene. Searching a
crime scene is a long and pains-taking process, however, it will yield many clues
when done properly. Once the evidence is found, recorded and packaged, it must
be sent to a crime lab for further processing. Each item when shipped should be
recorded, logged and accounted for from person to person so when used in a trial,
the evidence has been accounted for from beginning to end. The final thing
investigators must make sure is that all evidence was seized properly and with
probable cause. This is the main reason why in so many court cases evidence is
thrown out, improper searches and seizures. If any investigator is in doubt on
weather or not a place or person can be search, it is always best to obtain a
warrant for that such reason.
References
Hale, Charles D. Police Patrol. Operations and Management. Chicago:
John Wiley & Sons. 1991.
Saferstein, Richard. Criminalistics: An Introduction to Forensic
Science, Fifth Edition. Englewood Cliffs, New Jersey: Prentice
Hall Inc 1995.
Notes