Bloodstains are classified into three basic types: passive stains, transfer stains and projected or impact stains. What are the three main categories of paper? 12 different types of paper.
What are 3 factors that may affect blood stain pattern?
- Many factors affect the size and shape of the blood drops. …
- In addition to droplet volume, distance of fall and the blood source surface characteristics, other factors affect the size, shape and appearance of the bloodstains.
What is a group of bloodstains called?
Bloodstain Pattern – A grouping or distribution of bloodstains that indicates through regular or repetitive form, order, or arrangement the manner in which the pattern was deposited. Bubble Ring – An outline within a bloodstain resulting from air in the blood.
What are 3 things you can find out by looking at blood spatter patterns?
Pattern Analysis looks at the physical characteristics of the stain patterns including size, shape, distribution, overall appearance, location and surface texture where the stains are found. Analysts interpret what pattern types are present and what mechanisms may have caused them.
What are the 4 types of passive bloodstains?
- Passive. a. formed from the force of gravity acting alone. b. subdivided (drops, drip patterns, pools, clots) c. oozing or gushes from the body, dripping finger or arm, drops from a knife.
- Transfer. a. wet bloody surface comes in contact with a secondary surface. b. wipe, smudge, swipe or smear. c. …
- Projected blood spatter.
How do you categorize blood evidence?
From what may appear to be a random distribution of bloodstains at a crime scene, analysts can categorize the stains by gathering information from spatter patterns, transfers, voids and other marks that assist investigators in recreating the sequence of events that occurred after bloodshed.
What features of the bloodstains are important when determining the direction of travel of the blood droplet?
The “tail” or wave castoff of the bloodstain generally points to the direction of travel of the blood drop. The direction of travel and the angle of impact are referred to as the directionality of a bloodstain pattern. The directionality of a bloodstain will be used for reconstructing where the bloodshed occurred.
What are the two broad categories of bloodstain patterns?
Gardner and Bevel (In Press and 2004) have grouped bloodstain patterns into two basic categories; Passive stains and Dynamic stains. Passive stains result from an action other than a directed force to a blood mass. Examples would the bloodstain found in a crime scene from transfer or loss of blood by the victim.
How are passive bloodstains created?
Passive bloodstains are created or formed by the force of gravity acting alone. Bloodstain patterns resulting from blood exiting the body under pressure from a breached artery. By drawing a line through the long axis of a group bloodstains the point of convergence can be determined.
Whats a drip stain?
Drip Stain A bloodstain resulting from a falling drop that formed due to gravity. Drip Trail A bloodstain pattern resulting from the movement of a source of drip stains between two points.
What are the 5 things that blood spatter pattern can help determine?
Analysis of a spatter pattern can aid in determining the: • direction blood traveled. angle of impact. point of origin of the blood. velocity of the blood.
What are the differences among high medium and low velocity bloodstains?
Low velocity spatter can also result from pools of blood around the body and transfers. … This is classified as projected blood. A High velocity spatter is generally caused by a gunshot wound but can be from a wound from another type of weapon if enough force is used.
What are the six types of blood spatter patterns?
There are seven bloodstain categories: (1) passive bloodstain; (2) projected bloodstains; (3) impact spatter; (4) cast-off bloodstains; (5) arterial gush or spurt bloodstains; (6) wipe bloodstain patterns; and (7) transfer bloodstains.
What is the most common type of bloodstain pattern found at a crime scene?
The most common type of bloodstain pattern found at a crime scene is: Cast-off spatter.
What is meant by the first hit is free?
What is meant by “the first hit is free”? Which statement is true? Any person who opens a piece of evidence may be called upon to testify about that evidence in court.
What are the four main components of blood?
Blood is a specialized body fluid. It has four main components: plasma, red blood cells, white blood cells, and platelets. Blood has many different functions, including: transporting oxygen and nutrients to the lungs and tissues.
How do forensics determine blood type?
The test to determine your blood group is called ABO typing. Your blood sample is mixed with antibodies against type A and B blood. Then, the sample is checked to see whether or not the blood cells stick together. If blood cells stick together, it means the blood reacted with one of the antibodies.
What type of evidence is DNA?
Biological evidence, which contains DNA, is a type of physical evidence. However, biological evidence is not always visible to the naked eye. DNA testing has expanded the types of useful biological evidence. All biological evidence found at crime scenes can be subjected to DNA testing.
What three things determine the shape and size of a puddle when water is poured out onto a surface?
The shape and size of the puddle depends on the amount of liquid, the height of the container, and whether you spill on carpet, wood, linoleum or some other surface. In general, more liquid, or a fall from a greater height, will make a larger puddle.
What component of the blood spatter indicates the direction of spray?
What component of the blood spatter indicates the direction of spray? The head of the bloodstain.
What properties of blood determine the shape of a blood drop in flight?
The spherical shape is caused by the surface tension of the blood. Surface Tension causes the blood drop to pull itself in; both horizontally and vertically. The blood drop will settle into a spherical shape, as a result of the surface tension. surface.
What are the steps in the process of bloodstain characterization?
Bloodstain analysts use established scientific methods to examine bloodstain evidence at a crime scene including information gathering, observation, documentation, analysis, evaluation, conclusion and technical (or peer) review.
Who first suggested the grouping of bloodstain patterns?
History of Blood Spatter Analysis. The first methodical study of blood spatters, titled “Concerning the Origin, Shape, Direction and Distribution of the Bloodstains Following Head Wounds Caused by Blows,” was published in 1895 by Dr. Eduard Piotrowski of the University of Krakow in Poland.
What is an active bloodstain?
Active BLoodstains. BLoodstain patterns which are created by a force in addition to gravity; also known as blood spatter.
What bloodstains are created by gravity?
Passive Drop (Bleeding) — Bloodstain drop(s) created or formed by the force of gravity acting along.
What does the stringing method tell an analyst?
In the stringing method, which is still used by many analysts, the analyst documents the location of each spatter using the coordinate system. Then, he or she establishes a level line to show how the spatter is oriented in relation to the floor and ceiling.
How can directionality of bloodstains be determined?
Directionality of a bloodstain is defined by both the long axis of the stain and the presence of scallops, tails, and satellite spatter. These small characteristics appear in a greater concentration on the side opposite where the droplet first struck the surface.
Is it blood spatter or blood splatter?
Many people use the words spatter and splatter interchangeably. If you’d like to be precise, use spatter for small particles of liquid. Reserve the use of splatter for large messes.
What is impact angle?
The angle of impact is a mechanics concept that defines the acute angle formed by the plane tangent to the ground surface and the tangent to the trajectory. … In other words, the angle of impact represents the angle formed with the horizontal axis by an object hitting a plain surface.
What is a wipe pattern?
A type of blood spatter pattern produced when a bloody object such as a hand, clothing, or hair, is wiped across a surface like a wall…. …
What are to be determined in three dimensional impressions?
Three (3D) dimensional impressions that have 3 measurements, length, width and depth, are usually discovered outdoors in surfaces like dirt, sand, clay, mud, tar, or snow.
Why are blood spatter specialists usually called to the scene?
Bloodstain pattern analysts sometimes are called to gruesome scenes to gather crucial evidence regarding violent crimes. … Analysts can determine the trajectory of a projectile, the number of wounds a victim suffered, and how events unfolded during a violent crime.
What is the difference between a wipe bloodstain pattern and a swipe pattern?
– A wipe pattern is created from an object moving through a bloodstain, while a swipe pattern is created from an object leaving a bloodstain. … of blood spatter onto a target surface or object.
Which of the following reagent tests produces a pink color in the presence of hemoglobin?
Phenolphthalein is a presumptive test that reacts with the heme molecule present in blood. A positive reaction gives a pink color. While bloodstains normally appear red-brown in color, the color of the substrate or the age of a stain may affect the appearance or visibility of the stain.
Which type of blood stain is categorized as pools and drops of blood from a dead body that develops because of gravity?
Livor mortis, also known as lividity or hypostasis, is the gravitational pooling of blood to lower dependant areas resulting in a red/purple coloration. Although livor mortis is commonly seen between 2 and 4 h postmortem, its onset may begin in the ‘early’ period, as little as 30 min postmortem.
What are the 4 types of passive bloodstains?
- Passive. a. formed from the force of gravity acting alone. b. subdivided (drops, drip patterns, pools, clots) c. oozing or gushes from the body, dripping finger or arm, drops from a knife.
- Transfer. a. wet bloody surface comes in contact with a secondary surface. b. wipe, smudge, swipe or smear. c. …
- Projected blood spatter.
What are the two broad categories of bloodstain patterns?
Gardner and Bevel (In Press and 2004) have grouped bloodstain patterns into two basic categories; Passive stains and Dynamic stains. Passive stains result from an action other than a directed force to a blood mass. Examples would the bloodstain found in a crime scene from transfer or loss of blood by the victim.
What features of the bloodstains are important when determining the direction of travel of the blood droplet?
The “tail” or wave castoff of the bloodstain generally points to the direction of travel of the blood drop. The direction of travel and the angle of impact are referred to as the directionality of a bloodstain pattern. The directionality of a bloodstain will be used for reconstructing where the bloodshed occurred.
How are blood stains transferred?
Transfer stains result from objects coming into contact with existing bloodstains and leaving wipes, swipes or pattern transfers behind such as a bloody shoe print or a smear from a body being dragged. … This occurs when an assailant swings the bloodstained object back before inflicting another blow.
How do you analyze a bloodstain?
- Where did the blood come from?
- What caused the wounds?
- From what direction was the victim wounded?
- How were the victim(s) and perpetrator(s) positioned?
- What movements were made after the bloodshed?
- How many potential perpetrators were present?
What is a skeletonized bloodstain?
A bloodstain pattern that can arise if a blood drop is allowed to partially dry and is then wiped. Since the blood tends to be thinner at the edge of the drops, this portion dries first, leaving liquid in the middle.