Drawing upon data gathered during a three-year ethnographic study of homicide investigation in Britain, this paper explores how criminal justice actors use science and technology during homicide investigations and with what effect. Specifically, we present findings from an in-depth analysis of 44 homicide investigations across four British police forces and illustrate how the results from routine and cutting-edge scientific and technological techniques led to the identification, arrest and charge of the suspect. We consider how intelligence and evidence gleaned from science and technology sits alongside traditional approaches, such as information from witnesses and informants, in progressing such cases. We also consider the broader implications of the ‘scientification’ or ‘technification’ of police work to the unfolding homicide investigation trajectory.