Passive stains include drops, flows and pools, and typically result from gravity acting on an injured body. 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.
What are the two types of transfer blood patterns?
Swipe Pattern — the transfer of blood onto a surface not already contaminated with blood. One side is usually feathered which indicates the direction of travel. Wipe Pattern — created when an object moves through blood that has not completely dried and moves, removes, or otherwise alters it.
What are transfer blood stains?
Transfer/Contact Pattern — A bloodstain pattern created when a wet, bloody surface comes in contact with a second surface . A recognizable image of all or portion of the original surface may be observed in the pattern.
What is a print blood stain?
Bloodstain Patterns that May be Found
Bloodstains range in both amount of blood and type of pattern—from pools of blood around a body to obvious spatter patterns on the walls to microscopic drops on a suspect’s clothing. ... Right: bloody shoe print transfer pattern.
What are the six types of blood spatter patterns?
- 1902, Dr. John Glaister described 6 patterns: a. ...
- circular drops. b. arterial gusheswalls or ceilings produced by.
- pumping action of the heart. c. splashesshaped like exclamation points;аused to.
- d. smearsleft when victim or suspect touches surface. e. ...
- smears. f. poolsperson remains in one place bleeding heavily.
What are the 4 types of bloodstain patterns?
- Passive Bloodstain. Passive Bloodstain on a rough surface (such as wood or concrete)
- Projected Bloodstain. Projected Bloodstain, possibly a Cast-Off Pattern or a HVIS.
- Transfer Bloodstain.
What is the difference between blood spatter and blood transfer?
The blood drop will settle into a spherical shape, as a result of the surface tension. surface. SPATTER VS TRANSFER: The simplest type of blood spatter analysis is determining spatters from transfers. ... Transfers occur when a blood source comes in direct contact with a target surface area.
What is a void pattern?
Void patterns, or the absence of blood within an otherwise continuous bloodstain pattern , have been traditionally used by analysts for a number of purpos- es. ... Void patterns may also re- veal the precise position of clothing on an individual at the time of the bloodletting incident.
What is the difference between a wipe 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 .
How Does height affect blood spatter?
The height from which the blood falls will affect the size of the stain, with greater heights tending to result in larger bloodstains. ... A greater force will typically produce smaller droplets, with the density of blood drops decreasing moving further away from the initial blood source.
How do you identify blood stains?
Luminol is often combined with hydrogen peroxide to react with the heme groups in blood, producing a bright blue glow, known as chemiluminescence. This glow allows crime scene technicians to detect blood that has dried on surfaces or to detect blood that someone tried to clean from a surface.
Can blood erase fingerprints?
Summary: Careful criminals usually clean a scene , wiping away visible blood and fingerprints. However, prints made with trace amounts of blood, invisible to the naked eye, could remain. Dyes can detect these hidden prints, but the dyes don’t work well on certain surfaces.
What type of blood stain is a handprint?
Transfer Stains : These occur by objects or surroundings coming into contact with the blood. These can be drag marks, cloth patterns, shoe/footprints, handprints, fingerprints, wipes and swipes. Projected/Impact stains: These occur by the blood that travelled in the air.
What two forces act on a falling drop of blood?
In this simple scenario, gravity and surface tension play the greatest role. However, keep in mind that other inertial forces will also affect the droplet if the weapon is swung. The droplet will take on a teardrop shape for a very brief moment as gravity overtakes its surface tension.
Will blood of one person freely mix with another?
Blood is the circulating tissue consisting of two types of cells: red blood cells and platelets. Red blood cells (erythrocytes): ... In 1900, Karl Landsteiner found that the blood from one person: did not always freely mix with blood from another person .
What shape does a passive drop of blood at a 90 degree angle have?
When a droplet of blood strikes a surface perpendicular (90 degrees) the resulting bloodstain will be circular . Blood that strikes a surface at an angle less than 90 degrees will be elongated or have a tear drop shape.
