So What Did Margie Say About...CSI Fallen Angels

The repeat CSI: Crime Scene Investigation episode "Fallen Angels" airing on 3/27/13 was packed full of great forensic evidence.

 

It began with the shooting victim in the graveyard. Two cartridge casings that were located were considered not related due to their condition.  This occurs when a scene happens in an 'active' area where shootings or drug activities or excessive parties take place.  There is a tremendous amount of trash that must be "weeded out" from potential evidence that is relevant to the current event being investigated.  Usually the rule of thumb is to collect it even if there is a doubt but there are some scenes where it is sadly obvious that cartridge casings or syringes or used condoms have been there for quite some time.

 

They spoke of the lack of stippling in reference to the gunshot wound to the Reverend.  When a gun is fired the striking of the primer creates a small explosion which causes the gunpowder in the cartridge to ignite and send the bullet spiraling through the barrel of the weapon.  The unburned powder creates a pattern when it hits an object or a body.  When none is present this is an indication that the muzzle to target distance is such that the particulates fall away and don't hit the object or the body.  This gives a minimum distance that a weapon could be when fired.

 

The Medical Examiner utilized an Alternate Light Source to scan the body to search for potential evidence.  Some things absorb the light while others reflect certain wavelengths of light.  These reactions indicate a location to swab or collect potential evidence.

 

The fingerprint processing of the batteries in the flashlight is right on target.  Even when the item itself is wiped clean or contaminated with blood or dirt, there is a good chance that the protected batteries inside the item may provide at least a partial print.

 

There were several trace pieces of evidence but I will skip to my all time favorite form of evidence to help in an investigation: the BLOODSTAIN PATTERN!  The impact spatter on the top surface of the tennis shoes established that the wearer of the shoes was close to a blood source (the victim's head) when a forcible event (the shooting) occurred.  Blood spatter sizes are a clue to the force behind the forcible event.  The smaller the stains then the more force behind the event.

 

Great episode - worth the repeat.