1. CRIME SCENE RECONSTRUCTION:
BLOODSTAIN PATTERN ANALYSIS
Project Presentation By:
Lauren Brown, Ta’Asia Glass & Austin Mutuana

2. Defined as the method used to support a likely sequence
of events at a crime scene by the observation and
evaluation of physical evidence and statements made by
individuals involved in the incident.

3. Forensic Scientists work together to
reconstruct events that occurred before,
during and after the crime.
Law Enforcement secures the crime scene to
avoid altered , contaminated or destroyed
evidence.

4. Preliminary examination of the crime scene.
 Each crime scene has it’s own
circumstances.
Physical evidence is a critical factor for crime-
scene reconstruction.
 Observations are recorded by the
following methods:
 Photographs
 Notes
 Sketches

5.  Next, a hypothesis is developed to determine the
course of events that took place.
 By carefully collecting physical evidence and
thoroughly documenting the crime scene, the
investigator can unravel the series of events that
occurred during the commission of the crime.

6. Law Enforcement Personnel, Medical Examiner and/or
a Criminalist work together as a team to answer…
 Who?
 What?
 When?
 Where?
 Why?
 How?

7.  Trained medical examiners can determine whether the
body has been moved after death by evaluating the livor
distribution throughout the body.
 The collection, documentation and interpretation of
physical evidence is the foundation of the reconstruction.
 Reconstruction develops a likely sequence of events.
 Analysis of all data will help create the workable
reconstruction model.

8. Crimes involving violent contact often
involve blood stain patterns.

9. Information uncovered by bloodstain pattern includes:
 The direction which the blood originated.
 The angle at which the blood droplet struck a
surface.
 The location or position of the victim at the time of
wound infliction.
 The movement of the victim at the scene.
 The minimum number of blows the victim received.
 The approximate location of the person delivering
the blows.

10.  Surface Texture is vitally important when interpreting
bloodstain patterns.
 Harder non-porous surfaces such as glass result in less
spatter.
 Rough surfaces such as concrete result in irregular
shaped spatter possibly a satellite spatter.
Satellite Spatter is small drops of blood
distributed around the perimeter of a drop
of blood and were produced as a result of
blood impacting the target surface.

11. The angle of impact is formed between the path of a
blood drop and the surface that it contacts.

12.  Impact spatter is the most common type of
bloodstain pattern found at a crime scene.
 Occurs when an object impacts the source of
blood.

13.  Forward spatter travels away from the source in the
same direction as the force that caused the spatter.
 Back spatter also called blow-back spatter is blood
directed toward the source of the force that caused
the spatter.

14.  Not all bloodstains appear as spatter patterns, different
circumstances often create other type of stains.
 Contact/Transfer Patterns occur when an object with
blood touches an object that did not have blood on it.
 Examples of transfer:
 Fingerprints
 Tool prints
 Handprints
 Footwear prints
 Fabric prints in blood

15.  Sizes and shapes maybe seen in general transfer,
which can result in narrowing down possible tools.
 Individualistic features may point to the tool that
made the patter.
 Simple Transfer Patterns occur when a bloody object makes
contact with the surface and isn’t moved afterwards.

16.  Swipe Patterns occur when movement of a
bloody object across the surface takes place.
 The first transfer patterns will be dark and as it
moves it will become lighter and lighter.

17.  Flows-drops are large amount of blood that is
pulled by gravity.
 Flow may show movement of the object while
blood was flowing or after blood has dried .
 Different situations can lead to specific
patterns which can determine the movement
or non-movement of an object or body.

18.  Pools occur when blood is collected in a stable
undisturbed level.
 Analysts are able to analyze and estimate the
drying time of the stains of different sizes.
 The important part of pool stains is being able
to give a time of the events that led up to the
incident.

19.  Even after wiping up the stain, skeletonization
remains intact around the edges of the surface .

20.  Drip trail patterns are a series of drops that are
separate from the patterns.
 Can result from blood dripping off an object or injury.
 The dripping pattern in normally left by the suspect it can
determine the direction and the speed at which the person
was moving.

21.  Blood spatter patterns of any kind can provide a great
deal of information about the series of events that
took place at a crime scene.
 Investigators should note, study and photograph each
pattern and drop, to ensure there is an accurate record
of location and to distinguish laboratory samples.

22. Photographs and sketches should be taken by investigators to
show orientation of the patterns to the scene.

23.  There are two important methods of
documenting bloodstains.
 The grid method consists of setting up a
dimension over the entire pattern with
stakes and string
 The perimeter ruler method consists of
setting up rectangular borders of rulers
around the pattern.

24. QUESTIONS