Forensic Science Proper Crime Scene Techniques Essay

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 searched. The

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.


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.



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