Running head: INVESTIGATION OF BLOODSTAINS

Investigation of Bloodstains

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The crime scene photographs indicate that someone was attempting to cover up a crime

by cleaning up although some blood spots are still visible. Evidence of a cover-up shows that the

crime being investigated at this scene is a homicide. Luminol analysis indicates that the victim

lost a lot of blood and the chances of them being alive are very slim.

“Bloodstains can be categorized into three types; passive, transfer, and projected stains.

Passive stains comprise of pools, drops, and flows and usually result from gravity acting on an

injured body. Transfer stains occur when a bloody surface comes into contact with another

apparent, transmitting blood to that secondary surface. Projected stains result from the release of

pressurized blood on a surface” (NFSTC, n.d.).

Based on the photograph the pattern of the bloodstain could be projected bloodstain.

Blood is ejected from the artery as the heart continues to beat and as the blood travels it breaks

up into smaller distinct droplets. Projected stains result from releasing a large volume of blood

when the direction of the bloodstain hits a surface a large central stain if formed and is usually

surrounded by several spines of varying lengths.

The appearance of this peripheral stain can be valuable to an investigator since it aids in

determining whether a volume of blood forcefully struck an object or a surface. Projected

bloodstreams that fail to strike perpendicular surface progress alongside unique paths until they

land on a flat surface. The blood spatter on the door may be spattered since it exhibits a sense of

direction and is related to a blood source that was exposed to an external force as well as friction

and gravity.

According to Castello, Alvarez & Verdu (2002), “luminol is merely a presumptive test

reagent, and there is a possibility of obtaining a false negative after contaminating the specimen”.
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A diluted specimen can only be visualized through luminol which makes it difficult to carry out

further analysis to affirm the presence of blood. The reagent reacts with cobalt, copper ions, iron,

and copper compounds. It also reacts with potassium permanganate which increases the

likelihood of giving false reactions and inaccurate results.

Studies indicate that luminol causes the loss of various generic markers and further

dilution of an already diluted stain. Since it is liquid based, it can cause bloody impressions and

latent to smear which the reason why I believe that the bloodstains in the photograph are altered.

Dilution may push the stain beyond the generic marker analysis detection limits.

Fluorescence is a physical occurrence during which a substance is automatically excited

by immersion of considerable electromagnetic energy and consequently emits light. It

characterizes a subdivision of cold-light discharge-luminescence. The source of fluorescence is

associated with the material's capability of absorbing electromagnetic energy and successively

releasing the additional energy in the form of individual emission radiation. It arises when light

of a particular pigment and light frequency strikes an item, and it subsequently outlays light of a

diverse frequency and color.

According to Penven (2013), “fluorescence has a lower intensity compared to the light

beam that created it, therefore, for an analyst to visualize the scene they must use percolation that

wedges the detectable light but passes the fluorescence”. Even though blood does not fluoresce,

other liquids can. UV light excites the luminophore on the walls of a tube which in turn emits

visible light. Slight alterations in the chemical make-up of the luminophore can change the

chromaticity of the emitted light. UV lighting can also reveal fluids such as saliva, urine, and

seminal fluid. Additionally, certain narcotics fluoresce in addition to teeth and bone fragments.
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Because there was a clean-up my task as an analyst is to determine if the stains are

altered, spattered, or passive based on the enhanced images. In my opinion, the bloodstains on

the floor indicate that there was a large pool of blood and it can be altered due to the cleaning. It

is a wiped bloodstain since it has features that illustrate the occurrence of a physical change in an

altered stain. An altered bloodstain results from an object moving through a preexistent bloody

surface.

I would categorize the bloodstain as being void since there is no body. Void patterns are

beneficial for determining the location of a victim and assailant within a crime scene. The lack of

blood in a rather constant bloodstain pattern implies the existence of an intermediary target that

may have been moved. Using both Fluorescein and Luminol can help in accomplishing the

process however it should be conducted during the night or in a darkened room.

During photography and analysis, the ambient light should not be too strong to subdue

the fluorescent reaction. In this case, Luminol was used to heighten blood spatter evidence in a

crime scene. “It is usually the reagent of choice because when applied to bloodstains, even if it's

diluted, it will cause it to luminesce in the dark. Ambient light is beneficial when taking

photographs because it assists in revealing the appropriate regions nearby the fluorescing stains,

placing the luminous stain in the crime scene” (Schiro, 2016). If the light is insufficient, a

moderate flash can be used, set at approximately two to three stops lower than the coverage used

for the fluorescence alone.

Bloodstain evidence can be gathered for blood pattern analysis by cutting away stained

materials and surfaces, taking pictures of the bloodstains, and dehydrating and packing stained
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objects. If the bloodstained object is small and transportable it can be packaged in an envelope or

paper bag.

The advantage of a dried surface is that is needs minimal amount of interaction with the

bloodstains by the analyst. The demerit is that such a surface increases the workload of a

serologist if the items require more storage space. The equipment for gathering blood spatter

evidence typically consist of high-quality video and still cameras, evidence packaging, and

sketching materials.

Whenever possible, crime scene analysts prefer collecting the evidence while it's intact

which necessitates removal of sections of a carpeting or wall, furniture or other vast objects from

the scene and transferring them to the lab for examination. Immovable items such as concrete

flooring are normally documented and photographed.

Conclusion

Analyzing the initial crime scene photographs yielded additional evidence. The chemical

reagent, Luminol was used to identify the bloodstains that were cleaned up by the assailant.

“Thus, the reagent is more reliable than others because of a higher probability of producing false

positives and false negatives, in addition to being safer than other substances making it a

preferable choice reagent when carrying out presumptive tests” (Castello, Alvarez & Verdu,

2002).

Since the position of the body was altered and the bloodstains that used to be a pool of

blood on the surface seem to be void suicide can be ruled out, and the case is deemed as a

homicide. Based on the blood spatter pattern on the door it is possible that the victim was either

hit by a blunt object or stabbed and bled to death.

References

Castello, A., Alvarez, M., & Verdu, F. (2002). Accuracy, reliability, and safety of luminol in

bloodstain investigation. Canadian Society of Forensic Science Journal, 35(3), 113-121.

National Forensic Science Technology Center (NFSTC). (n.d.). Principle of Bloodstain Analysis.

Retrieved from A Simple Guide to Bloodstain Pattern Analysis:

http://www.forensicsciencesimplified.org/blood/principles.html

Penven, D. (2013, April 4). Crime Scenes and Alternate Light Sources. Retrieved from Crime

Scene Investigator Network:

http://www.crime-scene-investigator.net/alternatelightsources.html

Schiro, G. (2016). Collection and Preservation of Blood Evidence from Crime Scenes. Retrieved

from Crime Scene Investigator Network:

http://www.crime-scene-investigator.net/blood.html