Reflected near-infrared photography: Digging deeper into post-mortem examination

This research aims to investigate the utility of the Near Infra-Red (NIR) photographic technique in visualizing forensic evidence in a post-mortem examination.

A total of twenty-six deceased (male: n = 15; female: n = 11) were brought to the Mortuary of King George's Medical University, Chowk, Lucknow, Uttar Pradesh, India (226003), and were used to investigate the applicability of the human visible spectrum (HVS) & near-infrared photography. In the investigation, a modified Nikon D5300 crop-framed digital single-lens reflex camera was used for NIR Photography in combination with a Micro-Nikkor 105 mm, f/2.8, (Nikon Inc., Melville, NY, USA), Hoya R72 (760nm-860nm) infrared filter and a Nikon D5600 crop-framed digital single-lens reflex camera in combination with Nikkor 50mm lens for Human Visible Spectrum (HVS) Photography.

The finding of the study reported that the application of the NIR photography would be the best of the investigative techniques for visualization and photo-documentation of forensically relevant post-mortem findings, such as - trace evidences (e.g., blood spots & soil particles on dark clothing), in external findings (e.g., contusion on victim's body) also for internal findings in a road traffic accident (RTA), gunshot, and drowning victim (e.g., mud particles in the trachea of drowning victim & localizing contusion of the scalp in road traffic accident cases).

Human visible spectrum (HVS) photographs taken with Nikon D5600 provides substantial evidence for documentation purpose, the best results for trace evidence & contusion visualization in Post-mortem examination of the deceased were achieved with the NIR Photography in combination with indirect sunlight & room light as an infrared light source. (At a wavelength of 760nm-860nm).