So What Did Margie Say About...CSI: Backfire

 

The 4/10/13 CSI: Crime Scene Investigation episode titled "Backfire" showed an excellent forensic evidence collection and preservation technique and one procedure that was, in my opinion, far from excellent.

The wrapping of the beaten female victim in a tarp led to the collection of the tarp.  If you noticed, they put paper strips over the tarp to protect the evidence.  You should baffle an article like a tarp, a bed sheet, clothing articles, etc. so that no two areas of the evidence touches itself when folding it for packaging and/or transportation to the laboratory.  This procedure protects a transfer of biological fluids, trace, or other materials from one area of the evidence article from coming into contact with another section during the folding.  In doing it like this, any information obtained can be more substantial when running an investigation or testifying in court.

The second procedure that I would like to discuss is the stringing reconstruction of the bloodstain patterns.  The first thing that a bloodstain pattern analyst would do would create a 'wagon wheel' 2-dimensional reconstruction that would show the impact site.  From here, one would use the stains which were used to find the hub of the wagon wheel through their directionality to measure their length and width to determine a mathematical formula to determine the angle at which a particular stain struck the 2-dimensional surface.  From here the procedure allows the analyst to follow the angle and tie it off to a perpendicular structure which had been placed at the 2-dimensional hub of the wagon wheel.  What you have as a result is a 3-dimensional area in space where the blood source underwent the trauma which caused the impact spatter to fly in the air and strike the surfaces where they landed.  There was nothing close to this in the mass of wild strings that they had apparently arbitrarily placed at the crime scene.  The only thing close to realistic was the use of different color strings to distinguish individual patterns.

How disappointing that they wouldn't take the time to properly display the technique which could actually give them the information that they commented on in the show: the location of the victims when they underwent the beatings.