The purpose of this major research project was to contribute to law enforcement sector understanding of the relationship between benzodiazepine and pharmaceutical opioid misuse and crime in three select Australian jurisdictions (Victoria, Tasmania, Northern Territory) where there is evidence of illicit prescription pharmaceutical markets. This report focuses on the Victorian aspect of the study. While the primary focus of the study remains on law enforcement interests in relation to licit and illicit benzodiazepine and pharmaceutical opioid markets, these are discussed in relation to the broader public health implications of supply reduction efforts in a harm minimisation framework. The design for this study was based on that of the Illicit Drug Reporting Service. The research demonstrated that misuse and injecting of benzodiazepines and pharmaceutical opioids, especially morphine and buprenorphine, has become entrenched among some groups of PWID in Melbourne. The findings suggest that the drugs are diverted to the black market and can be sold for considerable profit, and are relatively easy to obtain on the street. They also suggest criminal behaviour may be related to the dependence on, and the use of, prescription drugs. In addition, uninhibited, aggressive, and bizarre behaviour, and feelings of invincibility, were attributed to the drugs, in particular benzodiazepines. (Executive summary, edited)