Police Life reveals the science behind crime scene processing!
By: Amanda Wong
A crime has been committed, and officers are on the scene. In the room where the offence was carried out are numerous clues that are invisible to the human eye, but which could lead to a breakthrough in Police investigations... And that’s where science and technology come in!
Police Life discovers how Forensic Specialists with the Home Team Science and Technology Agency (HTX) use a host of leading-edge tech tools to assist the Singapore Police Force’s Criminal Investigation Department in crime scene investigations.
Scene Processing: Blood Screening Kit
Blood evidence can be found at certain crime scenes and is crucial in providing potential leads. Forensic Specialists use presumptive blood screening kits to differentiate between blood traces and stains that could be mistaken for blood. This allows officers to identify relevant blood traces for collection and screening.
Recovering Evidence: Electrostatic Lifting Apparatus (ESLA)
Footwear prints can reveal important clues about the identity and movement of the suspects involved in a crime, as well as the sequence of events that occurred.
To preserve and collect footwear prints found at a crime scene, Forensic Specialists will deploy the ESLA. The ESLA contains a high-voltage power source to transfer impressions from the scene’s surface to a black lifting film.
Searching a Crime Scene: Forensic Light Source
Movement at a crime scene can be tracked when trace evidence, such as fingerprints, hair strands, bodily fluids or clothing fibres are transferred through physical contact or left behind. But trace evidence may not always be visible to the naked eye.
However, Forensic Specialists are undeterred. They employ specialised light sources to increase the visibility of trace evidence.
Preserving Evidence: Portable Fingerprint Development Chamber
Fingerprints serve as crucial identifiers of suspects. To recover and develop fingerprints at a crime scene, Forensic Specialists utilise the portable fingerprint development chamber.
The exhibit containing fingerprints is hung within a portable film chamber, inside of which cyanoacrylate fuming will take place. After the cyanoacrylate gas has crystallised, latent fingerprints will be detected on the non-porous surface of the exhibit. These can then be recovered and preserved.
Documenting a Crime Scene: Integrated Virtual Crime Scene System (IVCSS)
The IVCSS combines traditional scene documentation methods such as photographs with panoramic, high-resolution images of a crime scene. A consolidated visual interface provides officers with perspective views with related crime-scene information, allowing for a more comprehensive overview of scenes of interest.
Mixed Reality (MR) Training for Bloodstain Pattern Analysis
Besides crime scene processing, the HTX also leverages technology to enhance training. Human Factors and Simulation engineers have developed a MR training system to help officers recognise bloodstain patterns.
The trainer will first design a virtual crime scene with items of evidence such as weapons and bloodstain patterns. Trainees then process the scene virtually through a headset by marking out evidence, recording measurements and capturing photographs. These practice sessions can also be consolidated into a report for review and discussion.
“The MR training system is extremely versatile as it can project different bloodstain patterns in a real-life environment,” explained Ms Gladys Lim, Officer-in-Charge of a team of Crime Scene Specialists at HTX’s Forensics Division. “Training effectiveness is also increased as officers can learn the foundational concepts of bloodstain pattern recognition quicker, compared to conventional training!”
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