Which of the following is NOT one of the four main types of search techniques for detecting blood?

The identification of the four main types of search techniques for detecting blood is crucial for crime scene investigators. The correct choice, which indicates that infrared light is not one of the main types, is supported by the understanding of how blood detection works in forensic science.

Oblique light, luminol/Bluestar, and Leuco Crystal Violet are widely recognized methods used in crime scene investigations to identify the presence of blood.

Oblique light enhances the visibility of bloodstains by highlighting their texture and color variations, which makes them stand out against various backgrounds.

Luminol and Bluestar are chemical luminol-based reagents that react with the iron in hemoglobin, producing a luminescent glow that can reveal blood traces even after they have been cleaned up.

Leuco Crystal Violet acts similarly by turning dark blue when it reacts with hemoglobin, allowing for the visualization of bloodstains.

Infrared light, while useful in some forensic applications such as photography that may assist indirectly in contexts involving blood, is not specifically recognized for its role in blood detection techniques. Instead, it is primarily employed to reveal features that are invisible to the naked eye, such as latent fingerprints or other substances. Hence, it does not fit within the established primary methods for