Practising Crime Scene Investigation: Trace and contamination in routine work

The Crime Scene Investigator (CSI) has a distinct professional profile within the police. It is the CSI who is tasked with identifying trace at crime scenes in order to inform police investigations. Despite this significant role, little is known sociologically about the CSI’s routine work. This paper draws on ethnographic fieldwork completed at the National Policing Improvement Agency’s Forensic Centre, observation of CSIs at real crime scenes and interview data to consider the CSI’s practices surrounding trace at volume crime scenes. It foregrounds the work that take place in transforming crime scene trace into admissible evidence or objects for laboratory analysis and the processes of identifying meaningful trace, central to CSI claims of unique expertise. Yet beyond the crime scene and police environment, it is the CSI’s ability to record their adherence to prescriptive contamination avoidance procedures which is of paramount importance. This paper demonstrates the agency involved in making sense of crime scenes and the differing ways the CSI and CSI work are understood across police and courtroom environments.