Analysis of Bloodstain Patterns

In order to be an efficient bloodstain pattern expert (BPE), a tremendous amount of education in this field is necessary, as well as a lot of experience.  Many times bloodstain patterns overlap, the ability to determine this comes from the education and experience.  There are also a tremendous number of various bloodstain patterns at a single crime scene.  A BPE is crucial to this type of investigation but, it is important to weigh in all the evidence at the scene.  This includes firearms analysis, if present, bullet trajectories, DNA, and all crime scene photos.  (Young, 2011, pp. 287-289)

            As previously mentioned, there are a tremendous number of bloodstain patterns.  One of which consists of blood drops.  When a blood drop falls from the force of gravity alone; it can make many different size drops when striking a surface.  It is difficult to determine the length of the fall because you do not know what size the blood drop started with.  Another variation is the angle of the surface in which it strikes, the texture of the surface, such as, the absorbency of the surface and its ability to distort the drop.  When a blood drop is affected by a force other than gravity, it may change the characteristics of the blood drop as it strikes a surface.  (Young, 2011, p. 289)

            A blood drop in flight has slightly different characteristics than when affected by gravity alone.  Blood in flight is caused by a force other than gravity, but is also affected by gravity as all things are.  The velocity of the weapon directly affects the characteristics of the blood drops.  The direction the instrument was traveling to the point of impact.  A heavy blunt instrument can make blood spatters that are comparable to those of a bullet.  (Young, 2011, pp. 289-292)

            Now I will analyze the Molly Wright case.  David Hill claimed that he had found Ms. Wright’s body in the kitchen.  Mr. Hill had her blood on him which could be explained because he claimed that he had tried to revive her.  This could have been evidence that exonerated him.  The BPE in this case testified that he had blood spatters on him that could not possibly been made by the actions that he claimed that he had performed.  Therefore, without Samantha Warna’s testimony, justice may not have been served.  In my opinion, her testimony was extremely important in this case.  When a person bludgeons another person, blood spatters may be deposited on the perpetrator in the form of fine mist.  This depends on the weapon used and the force of the weapon at impact.  There could also be large deposits of blood, again, depending on the weapon and the force used.  (Young, 2011, pp. 297-298)

           

References

Young, T. (2011). Crime Scene Investigation: The forensic Technician's Field Manual. Upper Saddle River, New Jersey: Pearson Education.