The adaptation of a 360° camera utilising an alternate light source (ALS) for the detection of biological fluids at crime scenes

One of the most important and commonly encountered evidence types that can be recovered at crime scenes are
biological fluids. Due to the ephemeral nature of biological fluids and the valuable DNA that they can contain, it is
fundamental that these are documented extensively and recovered rapidly. Locating and identifying biological
fluids can prove a challenging task but can aid in reconstructing a sequence of events. Alternate light sources
(ALS) offer powerful non-invasive methods for locating and enhancing biological fluids utilising different wavelengths
of light. Current methods for locating biological fluids using ALS's may be time consuming, as they often
require close range searching of potentially large crime scenes. Subsequent documentation using digital cameras
and alternate light sources can increase the investigation time and due to the cameras low dynamic range, photographs
can appear under or over exposed. This study presents a technique, which allows the simultaneous detection
and visualisation of semen and saliva utilising a SceneCam 360° camera (Spheron VR AG), which was
adapted to integrate a blue Crime Lite XL (Foster + Freeman). This technique was investigated using different
volumes of semen and saliva, on porous and non-porous substrates, and the ability to detect these at incremental
distances from the substrate. Substrate type and colour had a significant effect on the detection of the biological
fluid,with limited fluid detection on darker substrates. The unique real-timeHighDynamic range (HDR) ability of
the SceneCam significantly enhanced the detection of biological fluids where background fluorescence masked
target fluorescence. These preliminary results are presented as a proof of concept for combining 360° photography
usingHDR and an ALS for the detection of biological stains,within a scene, in real time,whilst conveying spatial
relationships of staining to other evidence. This technique presents the opportunity to presumptively screen a
crime scene for biological fluids and will facilitate simultaneous location and visualisation of biological evidence.