So What Did Margie Say About....CSI

The repeat CSI: Crime Scene Investigation episode titled "Pick and Roll" airing on 3/13/13 helped show the wide variety of bloodstain evidence available in the investigation.

 

Spatter on the walls in the shower and also on the basketball jersey were both classified as being created by some forcible event.  Blunt force trauma created the spatter on the shower walls when the victim was beaten on and about the head.  This spatter not only established that a beating had occurred but that the victim was low to the ground when it happened.  The spatter on the jersey established that the person wearing the garment was close to the source of blood when the force was applied to create the blood loss.  In this circumstance, it was a punch to the vascular facial area which created a bloody nose in conjunction to the spatter from the nose injury.

 

When viewing the first deceased victim's body, blood helped to determine some information about time lines and wounds.  Bruising, which is blood under the skin, showed outlines of the "weapon" utilized to create the bruise patterns.  Some of the bruising established the existence of older injuries which meant that they were not related to the immediate damage caused at the time of death.

 

Clotting within the nasal area also helped to indicate an injury that was not consistent with the current wounds suffered at the time of the blunt force trauma as the cause of death.

 

The impressions in blood on the shower floor and adjacent floor displayed what is known as diminishing repetitive transfer patterns.  This simply means that when the source of blood is not replenished (like from a free flowing injury) but is merely from stepping into or coming into contact with a pool of blood or a separate source of blood, then a repeat motion that causes the bloody object to come into contact with another surface will leave patterns that become less and less distinctive.  Oftentimes details in a pattern can be established which gives a likelihood of what the particular bloody object is that creates the diminishing pattern.  Such was the situation with the woman's shoe pattern and the bouncing basketball pattern.

 

Of course this episode contained elements of masochistic behavior, love, greed and sports but what's more compelling than the blood evidence??