What are the two primary methods for detecting evidence at a crime scene?

The two primary methods for detecting evidence at a crime scene focus on utilizing visual techniques to uncover and document physical evidence effectively. The correct choice emphasizes the significance of using both normal eyesight and specialized lighting techniques, such as oblique lighting.

Visual inspection is fundamental in identifying potential evidence, as investigators systematically examine the scene for anything that may be pertinent to the case. The use of oblique lighting is particularly important because it can highlight textures and subtle features that may not be visible under standard lighting conditions. This technique helps reveal footprints, tool marks, blood spatter patterns, or other evidence that requires careful observation to be fully recognized and documented.

Both eyes and oblique lighting are essential tools in a CSI's skillset, allowing for a thorough examination of a crime scene, ensuring that no crucial evidence is overlooked. Other methods listed, such as interviewing witnesses or collecting samples, are important in the investigative process but do not directly correlate with the initial detection of physical evidence at the crime scene.