Detecting Blood Evidence

Описание: Detecting Blood Evidence


Light Source
Often this is the first tool used to investigate a crime scene.
Can cover large areas efficiently and can potentially identify more than just blood
Ex. Bodily fluids that are not visible under normal lighting conditions
Often high-intensity light or UV lights are used to help identify trace evidence



Blood Reagent Tests
These are examples of presumptive tests
Presumptive tests only confirm the presence or absence of a sample.
These tests, function based on the properties of hemoglobin in the blood and often use some type of chemical reaction, resulting in a color change.


Phenolphthalein
Typically referred to as the Kastle-Meyer test and produces a pink color when it reacts with hemoglobin.



HemaStix
A strip that has been coated with tetramethylbenzidine (TMB) and will produce a green or blue-green color with the presence of hemoglobin.


Luminol
This chemical can locate traces of blood, even if it has been cleaned or removed.
Investigators spray a luminol solution is throughout the area under investigation and look for reactions with the iron present in blood, which causes a blue luminescence.



Fluorescein
This chemical is similar to luminol and is also capable of detecting latent or old blood
It is ideal for fine stains or smears found throughout a crime scene.
After the solution has been sprayed onto the suspected area, a UV light and goggles are used to detect any illuminated areas



LCV or Leuco Crystal Violet
This chemical process is used the visual enhancement of blood to allow for easier photographs and analysis.



Link to Lecture Slides: https://drive.google.com/file/d/1_WKj...

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