Two podcast episodes describing how suspected marijuana is tested by forensic labs.
NIJ
Is It an Accident or Abuse? Researchers Develop Predictive Models for Pediatric Head Injuries
NIJ-supported research has enabled biomechanical experts to improve predictive models of head injuries in children, helping physicians and law enforcement to better distinguish between accidental injury and abuse.
Improving Analysis of “Trace DNA” Evidence
NIJ report on use of direct PCR which may eliminated the loss of DNA that traditionally occurs during DNA extraction and quantitation
Study Assesses the Accuracy and Reproducibility of Bloodstain Pattern Analysis
Black box study of bloodstain pattern analysts finds contrasting conclusions due to terminology; highlights importance of establishing consensus standards.
Study Assesses the Accuracy and Reproducibility of Bloodstain Pattern AnalysisRead More
The Forensic Microbiome: The Invisible Traces We Leave Behind
Field Sobriety Tests and THC Levels Unreliable Indicators of Marijuana Intoxication
Researchers investigated how marijuana affects skills required for safe driving and found that biofluid levels of THC did not correlate with field sobriety test performance or marijuana intoxication, regardless of how the cannabis was ingested.
Field Sobriety Tests and THC Levels Unreliable Indicators of Marijuana IntoxicationRead More
Forensic Footwear Reliability
Three NIJ-funded research articles on the reliability of footwear comparisons were published in 2020. Part I—Participant Demographics and Examiner AgreementPart II—Range of Conclusions, Accuracy, and ConsensusPart III—Positive Predictive Value, Error Rates, and Inter-Rater Reliability
Improving a Database to Help Identify a Vehicle by Using Paint Fragments
For years, investigators have relied on the Paint Data Query database to identify the make of a vehicle by matching the physical attributes, chemical composition, and infrared spectrum of the paint, primers, and clear coating layers. However, there are concerns with the database, generic coding being one of them.
Improving a Database to Help Identify a Vehicle by Using Paint FragmentsRead More
Linking Suspects to Crime Scenes with Particle Populations
Two scientists with a long record of research into the forensic value of very small particle populations examined cell phones, handguns, drug packaging, and ski masks from the San Diego County Sheriff’s Office examine whether such particles are valuable as physical evidence.
Linking Suspects to Crime Scenes with Particle PopulationsRead More
Microbial Communities on Skin Leave Unique Traces at Crime Scenes
Two related NIJ-supported studies evaluated the possibility of using an individual’s skin microbiome — a community of microorganisms that inhabit a specific environment — as a form of trace evidence from evidence found at a crime scene. The first study, led by Dr. Rob Knight of the University of California, San Diego, examined whether the …
Microbial Communities on Skin Leave Unique Traces at Crime ScenesRead More
Fire Research: Identifying Ignitable Liquids in Debris and Providing Error Rates to Strengthen Testimony
With funding from the NIJ, Dr. Michael Sigman and Mary Williams from University of Central Florida developed a method for analyzing fire debris samples that are highly contaminated with pyrolysis interferences. This technique provides an alternative objective method for classifying ignitable liquid residues, which is one of the only viable options for helping to progress …
Making Use of What’s Not Visible in Trace Evidence Examinations
Nanoparticles and other subvisible particles potentially present in nearly all trace evidence are often overlooked in forensic investigations. NIJ-supported researchers have characterized several types of particles and developed detection methods.
Making Use of What’s Not Visible in Trace Evidence ExaminationsRead More