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One of the most essential part of crime scene investigation are the part of a criminalist.
He is a partner of an investigation process that finds bits and pieces that even some
investigators don't see. Crime scene personnel can encounter blood evidence in many
types of cases, including burglaries and other non-violent crimes, but it is most often
encountered in crimes of violence such as homicide, assault, and sexual assault.
Bloodstain patterns are one of the most intriguing parts of forensic science that has
become more recognized today as not just a science but an art as well. The examination
of blood provides invaluable information to the forensic scientist in many areas of
criminal investigation. It determines whether or not if this was a violent crime, accident,
suicide, or natural death.
Blood is the most significant and frequently encountered types of physical evidence
associated with forensic investigation of death and violent crimes. Crime scene
reconstruction demands that we evaluate all physical and testimonial evidence to derive
some conclusions as to what occurred. The goal of bloodstain interpretation is to
reconstruct the crime scene utilizing the bloodstain patterns in answering our questions
whether the crime, which was committed, was violent in assisting in forensic
investigations. For homicide investigations, case resolution hinges on "careful and
intelligent examination of the scene". The nature of the blood spatter determines whether
or not this was a violent crime and helps the investigator in reconstructing the crime
scene. (Bevel, 2000)
Throughout history, bloodstain patterns were not appreciated as a forensic skill in
determining how a crime was committed and with what weapon. The first study in blood
interpretation was documented by Dr. Eduard Piotrowski in Poland. His work led this art
of work into a more useful skill in crime scene investigation and later was introduced into
the United States around the twentieth century. One of the first significant cases that
recognized bloodstain interpretation as a forensic science which solved many
investigations was the case State of Ohio vs. Samuel Sheppard in 1955. Dr. Kirk was able
to establish the relative position of the attacker and victim at the time of the
administration of the beating. He was also able to determine that the attacker
administered blows with the left hand, which was significant because Dr. Sheppard was
right handed. (James " Eckert, 1998) In 1982, further study and research was done by
MacDonnell who organized and researched bloodstain interpretation through training to
police agencies and criminalists. This lead to the art of bloodstain interpretation in
forensic science which increased considerably and today many are still contributing to
this field of study. Today, one of the biggest organization is the Advanced Bloodstain
Institute held in New York and holds around 300-350 members throughout the World.
This organization trains, explores, and researches basic courses for bloodstain
interpretation.
Bloodstain pattern interpretation is a discipline which involves many other fields of study
such as biology, physics, and mathematics. It is studied through the photographs,
clothing, weapons, or other objects regarding physical evidence. What is blood spatter?
And how do drops of blood play a role in crime scene investigation? Actually, it is called
Bloodstain Pattern Interpretation. It involves reconstructing the events that must have
happened to produce the bleeding. It is not something that most law enforcement officials
can do--it usually requires a specialist. The first step when dealing with blood in any
aspect of forensics/criminology is to know the characterization of bloodstains. (Gutierrez,
2002)
Blood can be characterized as a fluid substance that circulates in the arteries and veins of
the body. Blood is bright red or scarlet when it has been oxygenated in the lungs and
passes into the arteries; it becomes bluish red when it has given up its oxygen to nourish
the tissues of the body and is returning to the lungs through the veins and the tiny vessels
called capillaries. Blood consists approx. 8% of the total human body weight. Blood is
composed of a yellowish fluid, called plasma, in which are suspended the millions of
cells that constitute about 45 percent by volume of whole blood. It has a characteristic
odor and a specific gravity between 1.056 and 1.066. Bloodstains results from exposed
blood that has come in contact with external surfaces in the environment as a result of a
bloodshed event. (Fisher, 1981) When the circulatory system is disrupted by trauma or
disease, bloodshed occurs internally, externally or even both. Bloodstains are
characterized by their appearance on the various surfaces that the blood contacts
subsequent to bloodshed. The application of the physical properties of bloodstains
determines the basis for the study and interpretation of the location, shape, size, and
direction of bloodstains relative to the force of gravity. External forces can act upon
exposed blood, overcome these physical properties and create a variety of blood
formations, droplets, or spatters. They have been grouped into three main categories:
low- velocity, medium-velocity, and high -velocity impacts. (James, 1999)
The basic premise deals with the impact energy that is categorized into low, medium, and
high impact spatter. (Moore, 2002) Low velocity impacts are characterized by external
force applied to the blood source of up to 5ft. typical size of a bloodstain is 3mm in
diameter. Examples of low- velocity bloodstains are blood drops, splashed and projected
blood, or free-falling blood drops. Free falling blood drops can drip from clothing, hair,
weapons, or any object which can be determined if the person stood there after killing his
victim or violently killed its victim. The angle of impact is defined as the internal angle at
which blood strikes a target surface. The angle of impact is a function of the relationship
between the width and length of the bloodstain. (Eckert, 1997). Free falling blood drops
that fall vertically onto a horizontal surface impact at 90 degrees. The resultant
bloodstains are essentially circular in shape on a smooth hard surface. These drip patterns
will be large and irregular in shape with small circular forms. A projected bloodstain
pattern is a result of a rapid movement with when excessive blood is projected as the
result of force. For example, throwing up blood is projected blood in large amounts.
(Bevel " Gardner, 2001)
Blood droplets may strike a surface at any series of angles and directions. The tail of a
bloodstain generally point in the direction the blood droplet has traveled. When a blood
source is subjected to a force or impact, the resultant blood droplets may strike a target
surface at various angles and directions. A point of convergence is defined as a point to
which an individual bloodstain pattern can be traced or projected on a surface. This is
defined by tracing the route of the bloodstains to a common point or points. For example,
in the movie, it demonstrated using this method by using straws or strings to give the
direction and point of convergence of the bloodstains and reconstruct the crime scene in
order to determine if the cops were the first shooters or not. (Lee " Harris, 2000)
Medium-velocity impacts are characterized by external force applied to the blood source
between 5-100ft. The typical sizes of these bloodstains are between 1-3mm in diameter
although larger or smaller stains can be present. Examples of medium-velocity
bloodstains are beating with hammers, bricks, baseball bats, etc.. When these types of
bloodstain patterns are projected, they are distinguishable from low velocity bloodstains.
Medium velocity bloodstains consists of stains produced on a surface when the blood
source has been subjected to a force at a velocity. The energy of the impact causes the
blood to be broken up into small droplets such as coughing up blood, or minor incidents
such as slapping of a hand or object in blood. The occurrence of these events can often be
recognized and distinguished through careful examination of the entire crime scene, the
victim's injuries, and condition of the body. (Eckert, 1998) Impact velocities associated
with beatings and stabbings falls within this category. Blows administered to a victim
with sharp instruments will produce medium velocity blood spatter that may be
differentiate from high velocity spatters.
High-velocity impacts are characterized by external force applied to the blood source of
greater than 100ft. The typical size of bloodstains produced is less than 1mm diameter
although larger or smaller stains may appear. Examples of high-velocity impacts are
gunshot trauma, explosions, or machinery trauma. Acts of extreme violence often
produce a dispersion of blood volumes forced from a wound site Gunshot and other high
energy impacts such as blunt force or gunshot wounds, may disperse these blood volumes
along relatively flat trajectories. (Moore, 2002)
Blood is very uniform and reacts in predictable, consistent and reproducible manners
when impacted. Therefore, blood forced out entry and exit wounds is disbursed in a
prescribed manner. These are blood spatters from the victim's entrance and exit wounds
and are based on forward spatter and backward spatter. Back spatter is directed from the
back of the weapon and can be deposited on the skin or clothing. The amount of back
spatter is also affected by the type of weapon and ammunition and the anatomic features
of the wound site. Forward spatter is produced by blood droplets traveling in the same
direction as the source of energy and, in gunshot cases; it's associated with the exit
wounds. The bloodstain interpretations have been helpful in identifying whether or not it
was a violent death or something else. (Eckert " James, 1998)
In the cases of violent death, the external examination of the victim prior to the autopsy
by a forensic pathologist can reveal bloodstain patterns and changes within the body. For
example, if there are bruises on the skin that have an object shape than we can determine
with what object was used and how they struck the victim. The degree of postmortem
lividity or settling of blood within the body may help establish the approximate time of
death or whether the lividity is consistent with the position of the victim at the scene.
(The value of videotaping blood evidence is that the overall relationship of various blood
spatters and patterns can be demonstrated. One example of this could be a beating
homicide. (Lee " Harris, 2000) In this case, videotape can show the overall blood spatter
patterns and how these spatters are inter-related. The videotape can also show the
relationship of the spatters to the various structures at the crime scene. In cases where the
suspect may have been injured (such as stabbing homicides), the video camera can be
used to document any blood trails that may lead away from the scene. (Adams "
Krutisinger, 2000)
One of the important parts of bloodstain interpretation is the documenting, collecting, and
evaluation. Initial bloodstain evaluation at a crime scene should be able to provide the
investigator with the general nature of the activities that took place and relative
movements of victim and assailant. (James " Eckert, 1998) Crime scene areas are
documented either by photographs or videotapes. Videotapes can be an excellent medium
for documenting bloodstains at a crime scene. This is to record the evidence before any
major alterations have occurred at the scene. Videotape provides a perspective on the
crime scene layout that cannot be as easily perceived in photographs and sketches. It is a
more natural viewing medium to which people can readily relate, especially in
demonstrating the structure of the crime scene and how the evidence relates to those
structures. (Adams " Krutsinger, 2000)
The identification of blood and forensic serological studies for grouping and
interpretation of bloodstain spatters depends on the DNA make-up and genetic marker.
(Lee " Harris, 2000) Investigators must first remove bloodstained objects from the crime
scene for the submission to the laboratory. Once they reach the laboratory, scientists
group them together and run some ABO grouping tests to determine the age of the blood,
the quantity of the blood available, and environmental conditions to which the blood has
been exposed. Blood of the victim's ABO or enzyme type on suspect's clothing can prove
an invaluable link between the victim, crime, and perpetrator. A Forensic serologist
examines the blood left at the crime scene he then tries to distinguish it from human to
animal blood. Once this process is done, the serologist analysis it and groups it according
to its ABO group. The results are then compared to the victim's blood and suspect's
blood. (James, 1999)
In collecting bloodstains, if the bloodstain object can't be moved, the stains can be
collected onto swabs or cotton threads. The evaluation of bloodstains on clothing, objects
such as knives or handguns, or walls can tell a lot about this person and helps to establish
the involvement with the assault on the victim whether it was violent or not. The careful
examination of bloodstained clothing and footwear often provides valuable information
for accurate reconstruction of a violent crime. Bloodstain patterns on the victim's and
assailants clothing determines the position and movement during an attack or struggle
after blood has been shed. (James " Eckert, 1998) Bloodstain patterns on a suspects
clothing will confirm or refute explanations offered by the suspect concerning the reason
for his bloodstain clothes. (Lee " Harris, 2000)
If we can't find blood at the crime scene, we can detect blood through a process called
luminal. It produces a bright luminescence when in the presence of different amounts of
blood. It is a valuable tool for the investigator since it not only discloses the presence of
blood but its distribution. Luminol's reaction with a bloodstain spatter produces an
intense glow in many different patterns such as spatters, smears, or wipes. This test has
been debated because it reacts with many different chemicals such as house cleaners or
something in the substrate. (Fisher, 1981) Usually if there is no presence of blood,
chances are that criminalists will use luminal to determine where blood is present. For an
example, one case study showed where a woman was on her way home to change to go
out with a friend and the next day she was reported missing. Investigators found no traces
of blood in the victim's trailer home and her husband was known for marital abuse. Once
they lit the trailer with luminal blood was found on the couch and all over clothes. The
husband was found guilty of murdering his wife and luminal demonstrated that the
bloodstains had been cleaned up linking the husband to the crime. The luminol test works
best to discover an area where an attempt has been made to clean up blood. Research has
found that luminal is a successful reagent and, by using this method, investigators has
solved more cases by using luminal process. (Fisher,1981)
Blood analysis is very important in many different situations. For example, in forensics,
if a bloodstain pattern is obtained, analysis is vital. BPA (Bloodstain Pattern Analysis)
may on many occasions, clearly define the location of the victim or the assailant by
establishing the actions of either or both. All individual bloodstains which have resulted
from blood drop distribution are called spatter patterns. Although spatter patterns are
often emphasized over other bloodstains, they essentially involve class characteristics.
Class characteristics are those features which identify or separate other group from other
classes. (Wonder, 2001) Possible and impossible scenarios may be established to
determine if the victim, witness, or assailant is accurately describing what took place.
Numerous courts throughout the country have upheld the value and scientific reliability
of BPA. Court case information is available upon request. BPA is a valuable asset during
and after the initial investigation. BPA has been extremely valuable during the
establishment of the courtroom trial strategy. (Bevel " Gardner, 2001)
Case study shows how bloodstain pattern interpretation has solved many cases in
determining if these crimes are violent or not. Police were called to the scene of a fatal
shooting of young black man which occurred in the residence of his girlfriend. The cause
of death was a gunshot wound with the entrance wound located in the left posterior
parietal scalp in the kitchen. Investigators determined one of his drug deals went bad but
further investigated the bloodstain patterns and determined that small spatters of blood in
size range of medium to high velocity impact blood spatters was created by events other
than gunshot. (Eckert, 1998)
Another famous case in which successfully used bloodstain evidence is the case of the
State of Ohio vs. Samuel Sheppard. It was a famous case in which Houk had checked on
Marilyn Sheppard in her room and discovered there were blood spatters all over the walls
and police discovered she had suffered thirty-five blows to the head by some blunt
instrument causing her death. The murder of Marilyn Sheppard captivated the attention of
news media in an unprecedented manner and on December 21st, verdict was guilty to
second degree murder. This case opened a lot of interesting research in the blood analysis
field and it became more respected for its use. (Gutierrez, 2002)
One popular case study in regards to bloodstain pattern interpretation was the case a New
York City homicide case was investigated at the request of the District Attorney's office.
The deceased had been violently beaten about the face, neck, and chest area. The
bludgeoning left the victim unrecognizable, and produced bloodspatter patterns at the
scene that attained heights over nine feet. The suspect claimed that he reacted in selfdefense to the victim's attack with a table leg at which point he "knocked him down" and
possibly "kicked him a few times." Our investigation was intended to determine whether
the blood spatter patterns observed at the crime scene were consistent with the statements
made by the defendant. Conclusions were drawn from an analysis of the crime scene,
autopsy photos and report, physical evidence submitted to the laboratory, and
reconstruction experimentation performed at the Office of Chief Medical Examiner
(OCME). The spatter patterns observed at the scene were found to be consistent with
those that would be produced from a "stomping" incident. (Ristenbatt, 1995)
Bloodstain pattern analysis has made a notable contribution to the scientific investigation
of violent crime scenes by assisting with the reconstruction of the event in which blood
was shed. Since it is accepted in courts throughout the nation, analysis of bloodstain
patterns on crime scenes is routinely used by law enforcement. Both international and
U.S. based professional organizations recognize bloodstain evidence analysis techniques
as a valid investigative tool.
Bibliography
http://www.letsfindout.com
"Blood Type" - Encarta Encyclopedia "Forensics"- Encarta Encyclopedia
Adams, Thomas F " Krutsinger, Jeffery L. Crime scene investigation. Prentice Hall
Publishing. 2000
Bevel and Gardner. Bloodstain pattern analysis: With an introduction to crime scene
reconstruction. CRC Press. 2001
Fisher, Barry. Techniques of Crime Scene investigation. Elsevier Science Publishers.
Third edition. 1981
Gutierrez, Sherry. Bloodstain Pattern Analysis. Journal of forensic sciences.
www.jfklancerforum.com 2002
James, Stuart " Eckert, William. Interpretation of bloodstain evidence at crime scenes.
CRC press. 1998
James, Stuart. Scientific and Legal applications of bloodstain pattern interpretation. CRC
press. 1999.
Lee, Henry " Harris, Howard. Physical Evidence in forensic science. Lawyers and Judges
Publishing Co. 2000
Moore, Craig. Three-Dimensional models for bloodstain pattern analysis. Journal of
Forensic. Identification. 2002
Ristenbatt RR. A bloodstain pattern interpretation in a homicide case involving an
apparent "stomping". Journal of Forensic sciences. 1995
Wonder, A.Y. Blood dynamics. Academic Press. 2001
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what weapon first study interpretation documented eduard piotrowski poland work this
work into more useful skill later introduced into united states around twentieth century
first significant cases recognized interpretation science which solved many investigations
case state ohio samuel sheppard kirk able establish relative position attacker victim time
administration beating also able determine attacker administered blows with left hand
which significant because sheppard right handed james eckert further study research done
macdonnell organized researched through training police agencies criminalists lead
increased considerably today still contributing field study today biggest organization
advanced institute held york holds around members throughout world organization trains
explores researches basic courses pattern discipline involves other fields such biology
physics mathematics studied through photographs clothing weapons other objects
regarding physical what spatter drops play role actually called pattern involves
reconstructing events must have happened produce bleeding something enforcement
officials usually requires specialist first step when dealing aspect forensics criminology
know characterization bloodstains gutierrez characterized fluid substance circulates
arteries veins body bright scarlet when been oxygenated lungs passes into arteries
becomes bluish when given oxygen nourish tissues body returning lungs through veins
tiny vessels called capillaries consists approx total human body weight composed
yellowish fluid called plasma suspended millions cells constitute about percent volume
whole characteristic odor specific gravity between bloodstains results from exposed come
contact external surfaces environment result bloodshed event fisher circulatory system
disrupted trauma disease bloodshed occurs internally externally even both bloodstains
characterized their appearance various surfaces contacts subsequent bloodshed
application properties determines basis location shape size direction relative force gravity
external forces upon exposed overcome these properties create variety formations
droplets spatters they have been grouped three main categories velocity medium velocity
high velocity impacts james basic premise deals impact energy categorized medium high
impact spatter moore impacts characterized external force applied source typical size
diameter examples drops splashed projected free falling drops free falling drip from
clothing hair weapons object determined person stood there after killing victim violently
killed victim angle impact defined internal angle strikes target surface angle function
relationship between width length eckert free falling fall vertically onto horizontal
surface degrees resultant essentially circular shape smooth hard surface these drip will
large irregular shape small circular forms projected pattern result rapid movement
excessive projected result force example throwing large amounts bevel gardner droplets
strike series angles directions tail generally point direction droplet traveled source
subjected resultant droplets strike target various angles directions point convergence
defined point individual traced defined tracing route common points example movie
demonstrated using method using straws strings give direction convergence reconstruct
order determine cops were shooters harris medium impacts applied source between
typical sizes these diameter although larger smaller stains present examples beating
hammers bricks baseball bats types they distinguishable from consists stains produced
been subjected energy causes broken small such coughing minor incidents slapping hand
object occurrence events often recognized distinguished careful examination entire
injuries condition eckert velocities associated beatings stabbings falls within category
blows administered sharp instruments will produce differentiate high spatters applied
greater than typical size produced less than diameter although larger smaller stains appear
examples gunshot trauma explosions machinery trauma acts extreme violence often
produce dispersion volumes forced wound site gunshot energy blunt gunshot wounds
disperse volumes along relatively flat trajectories moore very uniform reacts predictable
consistent reproducible manners impacted therefore forced entry exit wounds disbursed
prescribed manner spatters entrance exit wounds based forward backward back directed
back weapon deposited skin clothing amount back also affected type weapon ammunition
anatomic features wound site forward produced traveling same cases associated exit
interpretations have helpful identifying death something else james prior autopsy
pathologist reveal changes within example there bruises skin object than determine used
they struck degree postmortem lividity settling within help establish approximate time
lividity consistent position value videotaping overall relationship various demonstrated
could beating homicide harris case videotape show overall inter related videotape also
show relationship structures where suspect injured stabbing homicides video camera used
document trails lead away adams krutisinger important parts documenting collecting
evaluation initial evaluation should able provide investigator general nature activities
took place relative movements assailant areas documented either photographs videotapes
videotapes excellent documenting record before major alterations occurred videotape
provides perspective layout cannot easily perceived photographs sketches more natural
viewing people readily relate especially demonstrating structure relates those structures
adams krutsinger identification serological studies grouping depends make genetic
marker harris investigators must remove bloodstained objects submission laboratory once
reach laboratory scientists group them together some grouping tests quantity available
environmental conditions exposed enzyme type suspect prove invaluable link perpetrator
serologist examines left then tries distinguish human animal once process done serologist
analysis groups according group results then compared suspect collecting moved
collected onto swabs cotton threads evaluation objects knives handguns walls tell about
person helps establish involvement assault careful bloodstained footwear provides
valuable information accurate reconstruction assailants position movement during attack
struggle after shed suspects will confirm refute explanations offered concerning reason
clothes find detect process luminal produces bright luminescence presence different
amounts valuable tool investigator since only discloses presence distribution luminol
reaction produces intense glow different smears wipes test debated because reacts
different chemicals house cleaners something substrate fisher usually there presence
chances criminalists luminal where present showed where woman home change friend
next reported missing investigators found traces trailer home husband known marital
abuse once trailer luminal found couch over clothes husband found guilty murdering wife
demonstrated cleaned linking husband luminol test works best discover area attempt
made clean research successful reagent using method solved fisher analysis very
important situations forensics obtained analysis vital occasions clearly define location
assailant establishing actions either both individual resulted drop distribution although
emphasized over essentially involve class characteristics class characteristics those
features identify separate group classes wonder possible impossible scenarios established
witness assailant accurately describing took place numerous courts throughout country
upheld value scientific reliability court information available upon request valuable asset
during after initial extremely during establishment courtroom trial strategy bevel gardner
shows solved determining police were fatal shooting young black occurred residence
girlfriend cause wound entrance located left posterior parietal scalp kitchen determined
drug deals went further investigated determined small range created events another
famous successfully used state ohio samuel sheppard famous houk checked marilyn room
discovered over walls police discovered suffered thirty five blows head blunt instrument
causing murder marilyn captivated attention news media unprecedented manner
december verdict guilty second degree murder opened interesting research field became
respected gutierrez popular regards york city investigated request district attorney office
deceased violently beaten about face neck chest area bludgeoning unrecognizable
bloodspatter attained heights nine feet claimed reacted self defense attack table knocked
down possibly kicked times intended observed consistent statements made defendant
conclusions drawn autopsy photos report submitted laboratory reconstruction
experimentation performed office chief medical examiner ocme observed those would
stomping incident ristenbatt made notable contribution scientific scenes assisting event
shed since accepted courts nation scenes routinely enforcement both international based
professional organizations recognize techniques valid investigative tool bibliography http
letsfindout type encarta encyclopedia forensics encarta encyclopedia adams thomas
krutsinger jeffery prentice hall publishing gardner introduction press barry techniques
elsevier publishers third edition gutierrez sherry journal sciences jfklancerforum stuart
william scenes press stuart scientific legal applications press henry howard lawyers
judges publishing moore craig three dimensional models journal identification ristenbatt
involving apparent stomping journal sciences wonder dynamics academic
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