Reference no: EM132258066

150 words agree or disagrees

Select two different types of bloodstain patterns discussed in this week's readings, describe each pattern, explain what causes each pattern and what each pattern can reveal to investigators, and finally describe how to properly document bloodstain pattern evidence.

Blood stain pattern analysis is a vital part to a crime scene. It can reveal many aspects and additional pieces of evidence. By studying the way the stain is positioned and the size as well as the orientation of the spatter, the investigator can determine the direction, the angle and most often the weapon or action that caused the blood stain.

Arterial spray - this pattern is identified as a bloodstain, categorized as a spurt, with the spatter in a linear orientation. This pattern occurs when blood is being pushed out of the body in a stream that is under pressure. This happens most often when an artery or the heart is ruptured.

This pattern will show a large volume of blood with a series of related linear stains as well as several flows from either individual stains or the primary stain itself. This pattern will also have large elliptical stains or overlapping staining in arcs, serpentine or overlapping patterns (Bevel & Gardner, 2008). Investigators seeing this pattern will immediately know that there is a severely injured/deceased victim and that there is going to be a weapon that is capable of puncturing or lacerating an artery, such as a knife. If the victim is not immediately visible, due the amount of blood loss, there will be a trail that will be able to be followed and unfortunately it will not be too far away.

Expectorate spatter - this blood stain pattern is identified as a bloodstain and categorized as non-linear impact spatter. This pattern occurs when blood is forcible expelled from the nose, mouth or respiratory system while under pressure. There will be a series of related spatter that varies in size.

The color of the spatter can be diluted due to being mixed with other bodily fluids. It is very common to find air vacuoles or bubble rings and mucus strands, as well as skin cells (Bevel & Gardner, 2008). Investigators seeing this pattern will expect to find a victim with facial, neck, or chest injuries. This injury could be caused by various methods either with or without a weapon, such as the victim sustaining internal injuries from a fight or simply a bloody nose or mouth injury.

Documenting bloodstain pattern evidence is very important. Due to the nature of bloodstain evidence, it is necessary that it be done properly the first time. According to Bevel & Gardner (2008), there are several steps that can be done to properly document the bloodstains for evidence as well as ‘maps' for scene reconstruction. The scene must be documented before it can be collected.

To begin, the entire scene must be photographed in situ. This means that before anything is collected or removed, the area must be photographed as it was originally found. If possible, this includes the victim, as well as where the victim is in relation to the rest of the scene. Once the victim is removed, the area must be photographed again to show anything under the victim. The photographs of the area must include floor to ceiling- if inside- as well as each picture overlapping the previous one.

Once this is completed, each blood stain must be photographed. An overall shot is taken first, then each stain of interest is macro-photographed with a reference scale in each picture. Once all basic photographs are taken, the examiner will take another series of photographs by using the road mapping techniques. All of the pictures taken will lead the viewer from an overall picture of the scene to individual stains. These pictures will serve as references for the examiners as well as evidence in the court room.

A highly weathered skeleton is recovered from a remote wooded site. Only the upper torso and cranium were recovered. The clavicle is found to be unfused and the cranium features a very prominent brow bone and sharp protruding mastoid process. What can be surmised about the victim's identity from this information?

Despite the severe lack of evidence that a skeleton provides, there is usually enough evidence still present to make some basic determinations such as age and gender, and in some cases an identification. In this scenario, the remains are as follows:

An unfused clavicle - this evidence can be used to determine the age of the victim. As a body matures, the clavicle begins to fuse together. The earliest that the clavicle begins to fuse is 15 years old, but most happen between the ages of 17-20 years old. The point at which the clavicle changes from ‘fusing' to ‘fused' is approximately 21 years of age in a female and 20 years of age in a male (Langley, 2016).

A very prominent brow bone - this bone can be used to determine the race of the victim. The brow bone is prominent and well developed in those of the Caucasoid race (Forensicmd, 2010).

A sharp protruding mastoid process - this bone can be used in determining the gender of the victim. The mastoid process is the bone that is located behind the ear to which the neck muscles are attached. The mastoid process in a male is longer and more prominent than in a female (Passey et al, 2015).

From the information described above, it would be my best determination that the skeletal remains were that of a white male under the age of 20.

Shira

Bevel, T., & Gardner, R. (2008). Bloodstain Pattern Analysis: With an Introduction to Crime Scene Reconstruction.

Langley, N. (2016). The lateral clavicular epiphysis: fusion timing and age estimation.

Forensicmd. (2010). Identification of skeletal remains.

Passey, J., Mishra, S., Singh, R., Sushobhana, K., Singh, S. & Sinh, P. (2015). Sex determination using mastoid process.