Origin-and-Cause Determination
Definition
The two-part forensic conclusion in fire investigation: the physical location where the fire started (origin) and the mechanism that produced the initial combustion (cause). Both must be established independently.
- Two components
- Physical location (origin) and ignition mechanism (cause)
- Field
- Fire and arson investigation
- Requirement
- Both established independently
Common questions
Why must origin and cause be determined independently rather than assumed together?+
Locating where a fire started does not by itself explain how it ignited there, and assuming a cause before confirming the origin risks confirmation bias, where an investigator interprets burn patterns to fit a preconceived cause. Standard methodology such as NFPA 921 requires the origin to be established through fire pattern analysis first, and the cause investigated separately from that confirmed location.
What happens to a cause conclusion if the origin determination later proves wrong?+
A cause finding tied to an incorrect origin becomes unreliable, since ignition sources, fuel packages and witness accounts are all evaluated relative to that specific point of origin. This is a common basis for successful challenges to fire investigation conclusions in both criminal and civil litigation.
Related terms
- ATF NCETR
- Bureau of Alcohol, Tobacco, Firearms and Explosives National Center for Explosives Training and Research, based at Redstone Arsenal, Alabama. The US federal...
- BDDS
- Bomb Disposal and Detection Service, operated by state police forces in India. Provides operational post-blast scene management and preliminary evidence collection, with...
- CFSL
- Central Forensic Science Laboratory: a central government lab operating under DFSS. India has CFSLs at New Delhi, Hyderabad, Chandigarh, Kolkata, Pune, Guwahati,...
- DSTL Fort Halstead
- Defence Science and Technology Laboratory site in Kent, UK. The principal institutional capacity for explosives forensic science in the UK, handling major...
- ENFSI EWG
- European Network of Forensic Science Institutes Explosives Working Group. Coordinates best-practice manuals, proficiency testing, and method harmonisation for explosives forensic science across...
- Ignitable Liquid Residue (ILR)
- Petroleum-derived or synthetic liquid accelerant residue surviving in fire debris. Identified by GC-MS against the ASTM E1618 classification system, which groups ILRs...
- NFPA 921
- US National Fire Protection Association Guide for Fire and Explosion Investigations. The internationally accepted methodology Indian fire investigators and SFSL fire divisions...
- Post-Blast Analysis
- The forensic examination of debris, fragments, and residues recovered from an explosion scene. Aims to characterise the explosive compound, initiator type, device...
- Undetermined (NFPA 921)
- The NFPA 921 conclusion category that records insufficient evidence to establish origin or cause at the 'possible' level or above. Represents the...