During the initial investigation phase, she introduces him to the basics of examining acquired evidence, as well as utilizing luminol and fingerprinting to obtain evidence.
The amount of catalyst necessary for the reaction to occur is very small relative to the amount of luminol, allowing the detection of even trace amounts of blood.
Thus, typically the iron-shaped cation found in the heme group of hemoglobin reacts with luminol observing a blue luminescence of the reaction itself is carried out.
