Scientific and Legal Developments in Fire and Arson Investigation Expertise in Texas v. Willingham
The forensic sciences, as a form of professional knowledge, are changing with new advancements in technology and continuing research and development. With the National Academy of Science's recent call for more research and testing of the forensic sciences, the criminal justice system is faced with the challenges of handling cases where convictions are based on outdated or discredited evidence. In light of technological advancements in the field, this article examines the evolution of fire- and arson-investigation knowledge over the course of a highly publicized capital murder case. The history of arson investigation is discussed, as is the legal admissibility of such expert testimony. Arson investigation expertise stems from non-scientific or experience-based origins, yet is conveyed in court as scientific fact. The article identifies the dangers of admitting such testimony into court without scrutiny. The lack of scientific validation of investigative methods, overreaching scientific claims based on case facts and witness statements, and fire investigators' susceptibility to contextual bias are discussed. The article raises questions as to whether and how the legal system has propagated the misuse of arson investigation testimony and how outdated understandings of evidence may impact the identification of future miscarriages of justice.
Unconfirmed accelerants
Fire investigation is arguably one of the most difficult areas of investigation. The fire scene and available evidence has often been burnt, melted, smoke-stained, water-damaged and trampled on, but the fire investigator still has to make important distinctions between whether a fire was accidental or deliberate (arson). Modern fire investigations often rely on portable electronic detectors to identify ignitable liquid residue (ILR), or accelerant detection canines (ADCs), trained on a number of target substances. An analysis of cases from England and Wales, the United States of America (USA) and Canada demonstrates that sophisticated admissibility frameworks have not been effective in rejecting opinion testimony given by investigators and dog handlers that unconfirmed dog alerts where laboratory tests were negative provided proof of arson. This is problematic and controversial, and the authors conclude that such testimony is not compatible with modern forensic or scientific standards and should not be admitted into courts.
How to Improve Forensic Science
Some institutional structures for inquiry produce better approximations to truth than others. The current institutional structure of police forensics gives each lab a monopoly in the analysis of the police evidence it receives. Forensic workers have inadequate incentives to produce reliable analyses of police evidence. Competition would create such incentives. I outline a system of “competitive self regulation” for police forensics.Each jurisdiction would have several competing forensic labs. Evidence would be divided and sent to one, two, or three separate labs.Chance would determine which labs and how many would receive evidence to analyze.Competitive selfregulation improves forensics by creating incentives for error detection and reducing incentives to produce biased analyses.