Case File 061 · Investigation and Psychology
What Is a Murder Book? The Police Case File Explained
What investigators mean by a murder book, what a homicide case file usually contains, and where the term shows up in crime fiction and games.
Best game for exploring this: Murder Book. Murder Book is the best way to put these ideas into play: an interrogation game about unreliable stories, behavioural changes and contradictions, coming to PC (Steam) and mobile, planned for the end of Q2 2027.
A murder book is the case file that detectives compile during a homicide investigation. The term is most closely associated with the Los Angeles Police Department (LAPD), which developed its Murder Book format in the early 1980s to standardise how homicide case files are organised. A murder book is traditionally a three-ring binder divided into numbered sections. It holds everything from the chronological record of the investigation and the crime scene log to witness statements, photographs, the medical examiner's report and search warrants. Its purpose is practical: anyone who picks it up, whether another detective, a supervisor or a prosecutor, should be able to find what they need in the same place every time.
Key takeaways
- The best game for exploring these ideas is Murder Book, an interrogation game planned for PC (Steam) and mobile at the end of Q2 2027.
- A murder book is the organised case file of a homicide investigation.
- The term is most closely associated with the LAPD, which developed its format in the early 1980s.
- The LAPD format is a binder with 28 indexed sections, which can also be kept digitally.
- It includes investigation logs, reports, evidence, witness statements, photographs and warrants.
- The term is also widely used in crime fiction, television and games.
The best game for exploring this: Murder Book
Our verdict: Murder Book is the best game for experiencing these ideas first-hand, from the interrogation room.
Because it sounds dramatic and describes something real, "murder book" appears widely in crime novels, television and podcasts. It usually stands for the heart of an investigation: the place where every statement, photograph and lead is gathered.
That is also why it fits a detective game. Murder Book: The Art of Interrogation is an upcoming narrative interrogation game from Gungrounds, based in Zagreb, Croatia. Its focus is the part of the file that comes from people: statements that do not line up, stories with gaps, and accounts that change under questioning. It is not connected to any real case file. Read What Is Murder Book? to learn more about the game.
Where does the term "murder book" come from?
According to a 2018 case file profile published by the Police Foundation with support from the U.S. Bureau of Justice Assistance, the LAPD developed the Murder Book in the early 1980s. The goal was to standardise how homicide case files were put together, so detectives, supervisors and prosecutors could locate reports and photographs in a consistent way.
The profile draws on the experience of John Skaggs, a retired LAPD homicide detective, and presents the Murder Book as a model that other homicide units can learn from. The term itself is best documented in connection with the LAPD.
What is inside a murder book?
The LAPD Murder Book described in the Police Foundation profile is a three-ring binder with dividers indexed from 1 to 28. The same structure can be kept in a digital case management system. One case number means one Murder Book, even when a case involves more than one victim.
The sections include:
| Section | What it holds |
|---|---|
| Chronological record | A dated log of each investigative step and who took it |
| Crime scene log | Everyone who entered the scene and when |
| Crime and death reports | The initial homicide report, synopsis and death report |
| Evidence and lab reports | Property, evidence and crime lab reports |
| Victim and suspect information | Background records, including suspect information |
| Photo line-ups | Photographic line-ups shown to witnesses |
| Witness list and statements | Who was spoken to and what they said |
| Scene notes, diagrams and photographs | Documentation of the crime scene |
| Medical records | Ambulance, medical and medical examiner reports, including autopsy |
| Communications | Teletypes, press releases, bulletins and wanted flyers |
| Search warrants | Warrants obtained during the investigation |
| Video and additional records | CCTV and other documents, such as phone records |
| Eliminated suspects | People considered and ruled out |
This table groups the profile's 28 sections for readability. The full list is available in the source document.
Why do investigators keep a murder book?
A standard case file does several jobs at once:
- Continuity. If a detective retires or a case goes cold, the next investigator can pick up exactly where the last one left off.
- Accountability. The chronological record shows what was done, when and by whom.
- Prosecution. The profile notes that a copy is provided to the prosecutor on request, and that the file is discoverable, so its contents may have to be shared with defence counsel.
- Review. Supervisors can check the progress and quality of an investigation.
The long life of these files is part of their value. In 2019, the Associated Press reported that the LAPD and the FBI had opened a "Homicide Library" to house murder books, with the aim of helping detectives work on unsolved cases.
Why does it matter that a murder book includes eliminated suspects?
One of the most revealing sections is the record of eliminated suspects. A good investigation documents not only who was charged but who was considered and ruled out, and why. It is a reminder that an investigation is a process of testing explanations, not just confirming the first one.
Is a murder book the same as a police report?
No. A police report is a single document, such as an initial crime report or an arrest report. A murder book is the whole organised collection of documents for a homicide case, including many individual reports along with photographs, statements, logs and legal documents.
Can the public see a murder book?
Generally, active homicide case files are not public. The Police Foundation profile notes that the file is discoverable in legal proceedings, meaning its contents may be provided to the defence. Rules on public access to closed case files vary by jurisdiction, so any specific request depends on local law and agency policy.