Drug cases may involve seizure of bulk quantities of imported drugs or allegations of clandestine manufacture. A forensic drugs expert may be able to comment on what synthetic route was attempted during manufacture. Whether amounts of drug seized suggest personal use or dealing chemical profiling from impurities and yield (how much drug can be manufactured from a given amount of precursor).
Alcohol is a common factor in many crimes, ranging from drink-driving to murder. A forensic alcohol expert can calculate, for example, whether what a person says they consumed could have resulted in a given blood/breath/urine alcohol concentration, how ‘drunk’ a person may have been after drinking a given amount of alcohol, or what a person’s blood, breath or urine alcohol concentration was at a particular time prior to the sample being provided.
Alcohol consumption is often considered in cases such as murder or rape where the level of intoxication may be a factor.