Purpose In the context of rising reports of rape, set against falling convictions, it has been argued that rape has been de facto decriminalised in England and Wales. This paper aims to explore how police and prosecutors investigating rape and serious sexual offences (RASSO) use and perceive investigation management documents (IMDs), and how high-quality IMDs may lead to better justice outcomes. IMDs must be started by police at the beginning of an investigation and should document: what an officer is/is not doing and why; what the reasonable lines of enquiry are and their outcomes; and what has translated to evidence and supports charge, disclosure or unused material. The document is shared with the crown prosecution service at the point a charging decision is sought. Design/methodology/approach Semi-structured interviews were conducted with 32 police officers and five crown prosecutors across five areas in Year 2 of Operation Soteria Bluestone, a project that aimed to improve how police investigate rape. These interviews were analysed using the qualitative method of thematic analysis. Findings Three main themes were identified relating to timeliness, understanding, and quality of IMDs. It was found that IMDs are not always started at the beginning of RASSO investigations or even at all. Officers also lacked understanding around the purpose of IMDs, often seeing them as duplications of other case files. Finally, prosecutors and police concurred that the quality of IMDs are generally poor and lacking in critical reflection. Originality/value To the best of the author’s knowledge, this is the first academic paper to consider the use of IMDs by police and prosecutors in RASSO investigations. As such, it is both a unique contribution to the field and also provides a platform for future research. Understanding how police officers can produce the highest quality IMDs, in a timely fashion, is of paramount importance given the wider societal context of increasing reports of rape alongside low charge rates. Implications for training are considered.