Biochemical Sciences Sections
The Biochemical Sciences Sections (BSS) consist of two sections, A and B, working in parallel. The primary aim of BSS is to identify and individualise the source of biological evidence collected at the scene of crime using DNA profiling technology. Cases received by the Sections are predominantly related to "offences against the person" such as homicide, sexual offences and assaults, and "property crime", such as burglary, theft and criminal damage. In order to assist law enforcement in their investigation and provide professional advice, the submitted case exhibits bearing biological materials are subjected to testing and comparison in order to ascertain their possible sources, for example, whether bodily fluid evidence, such as blood and semen, found in a sexual assault case is that of the suspect; if an alleged person could be the biological parent of an abortus in an infanticide case; and identification of human remains, such as bone and teeth, from a "Dead Body Found" case.
DNA extraction using a robotic system
Staff searching for DNA on an exhibit item
Apart from the routinely received serious and high-volume crimes, officers in the Sections are also involved in specialised investigations such as the interpretation of blood spatter patterns at crime scenes pertaining to homicide or serious assault cases in an effort to reconstruct the case scenario, as well as DNA analyses of submitted exhibits in deception cases in which, for example, dried rabbits' ears being used to disguise as fish maw, a Chinese food delicacy, and cases involving illegal trading or consumption of dog or cat meat.
Since 1998, Polymerase Chain Reaction (PCR)-based DNA profiling has been the principal analytical method for the examination of biological evidence. The DNA profiling kit routinely used in the Sections allows typing of twenty-six DNA characteristics plus sex determination. The Sections have always been striving to enhance the evidential value of biological evidence by maximizing DNA recovery, especially from compromised and challenging casework samples, and through exploring and employing different state-of-the-art processes in DNA analyses that will increase sensitivity, heighten the ability to overcome PCR inhibition, improve data quality and operational efficiency.
Key Instruments
The following instruments are used routinely by the Section:
- Genetic Analyzers
- Automated Liquid Handling Systems
- Sequence Detection Systems
- PCR Thermocyclers
DNA extraction using a robotic system
Examination of sperm under a microscope
Targets and Key Indicators
Key Performance Measures Relating to the Forensic Science Services
Targets
Targets are defined as the percentage of completed cases whose individual case-completion time does not exceed a specified number of working day(s)