Crime scene investigation often requires retrieval of evidence from water bodies. 90% of the time police divers work in zero visibility requiring painstaking fingertip searches to locate small objects such as shell casings, knives, guns etc. Manual searches are extremely slow (~1 week for a 100m stretch of water), but dive times are often limited by the conditions and physiological limitations. Waterproof metal detectors improve search times but they are adapted land based units with ~20cm diameter coils and a long handle. Form factor, haptics and setup makes then unsuited to underwater CSI. Pin-point detectors though compact and simple are not sensitive enough to eliminate fingertip searching. Continuous wave metal detectors don’t work if the water is brackish or if the bed has metallic mineralisation. Pulse induction can be used, but high power consumption limits battery life in a unit that is compact enough. This project will overcome these limitations by developing a unique hand-held, sensitive metal detector for underwater use in extremely challenging conditions. Whilst underwater CSI equipment is a niche market, the same feature set will appeal to the very large number of hobbyist divers (950,000 PADI certified p.a.) who are looking to add another dimension to their hobby. The importance and societal benefits of equipping CSI personnel with reliable, effective tools to search underwater cannot be under-estimated as the divers work under extremely hazardous conditions where they are at risk of illness (Weil’s disease, drug paraphernalia etc.), entrapment, hypothermia as well as all the normal diving risks.