Drawing upon qualitative data gathered during a four-year ethnographic study of homicide investigation in Britain, this paper explores how detectives, scientists, and other experts use findings from forensic sciences and technologies (FSTs) when constructing and modifying pre-trial homicide narratives. We consider how these narratives unfold from the earliest moments of the investigation and are told and re-told, as they are assembled into one coherent narrative fit for elocution in criminal court. We explore the embedding of findings from FSTs into narrative; the attention given to narrating character, motive, and intent; the use of narrative shifts to accommodate unwelcome findings from FSTs; attempts to deal with ambiguity during narrative creation; and, crucially, the reciprocal relationship between narrative and evidence. We suggest that narratives, such as those that we examine, are not mere chronologies, but the artful products of coordinated professional practice. Our research suggests that illuminating the origins and unfolding of such narratives during criminal investigation is as important as recording their final polished deployment within the theater of the courtroom.