Investigations | Section 2.4

Fundamentals of Criminal Investigation by Adam J. McKee

Section 2.4: The Case File

When a crime scene investigation concludes, the lead investigator must compile a case file for the investigation (depending on the department, the final collection of documents may be called the final report or prosecution report).  The case file is simply a systematic collection of all pertinent documents regarding a particular case.  The following documents from the crime scene and other investigative activity should be included in the case file:

  • complaint
  • preliminary investigation report
  • follow-up reports
  • statements
  • admissions/confessions
  • laboratory reports
  • photographs
  • sketches/drawings
  • summary of negative evidence

Complaint.  All crimes known to the police came to their attention in some way.  Most often, this is a phone call to 911 or another dispatch number. However that initial complaint was made, the record should be included in the final report.  At a minimum, it should contain the date and time of the complaint, the address of the incident, details of what the person making the complaint said, and the identity of the officers dispatched to the scene, and the time that they were dispatched.

Preliminary Investigation Report.  The first responder to a crime scene should conduct a preliminary investigation, and the results of and facts surrounding that investigation should be recorded in a formal written report.  This report can provide important information such as when officers arrived on the scene, conditions (e.g., weather and persons present) at the scene, and the actions of the first responders.

Follow-up Report.  Each time a significant lead is followed in an investigation, the actions taken by investigators and the results of those actions should be recorded.  Such reports should be added chronologically to the final report.

Statements.  Assemble all witness statements gathered during the investigation.  If witness statements were not obtained, then provide summaries of oral statements made during interviews.   

Admissions/Confessions.  All documentation of admissions and confessions should be included as a separate part of the report.  

Laboratory Reports.  Documents resulting from forensic laboratory analysis and the follow-up investigation should be added when they become available.  All laboratory reports should be included in the final report. Generally, investigators will want to include information about how these reports relate to other elements of the report.  

Media.  All relevant photographs, drawings, and sketches should be included in the final report.  Photographs.

Summary of Negative Evidence.  Any evidence that tends to hamper the state’s case must be included in the report.  This is necessary for the prosecutor to adequately argue against such evidence (e.g., witness statements that provide an alibi).  In addition, failure to reveal exculpatory evidence to the defense can result in a mistrial as this is legally required as part of the discovery process.   

Organizing Information

A key to clarity in report writing is organization.  Logically and as a matter of time-tested tradition, police reports are written in chronological order.  This usually means starting off with an explanation of how an incident came to the attention of police and ends with the final disposition in the case.  One way to view an incident is as a story, and all good stories have a beginning, a middle, and an end.

It is difficult to provide a general outline of a good report since the complexity of reports will depend largely on departmental policy and the complexity of the case.  A report on a “fender bender” may be as short as a few sentences, while a homicide investigation may result in a case file that contains thousands of pages of reports and supporting documents.  Different departments have different standardized forms, and those forms must be used and organized per policy.

Police report writers are advised to begin with a simple (informal) outline of what will be covered in the report.  Some departments will aid in this process by developing in-house checklists of things to include in specific types of reports.      

Key Elements of a Good Report

Reports are a critical part of policing because they record important details of an event and are used to help further investigations and as evidence in court. Therefore, police reports must be clear, factual, and concise. One often difficult part of the police report for officers to write is the narrative. This is a section in which an officer describes everything that she observed at the scene. Victims are identified, perpetrators are described based on witness statements, the scene (time and place) is recorded, and the situation is summarized. The narrative consists of facts.  A key element of good report writing is to stick to factual information and not include speculation or opinion.

Witnesses should be identified, and important details from their interviews may be included. If you have verbatim statements from a victim or witness, write exactly what he or she said in quotation marks.   

Grammar, Style, and Spelling.  Use correct spelling, punctuation, and grammar. Police reports become part of the public record and may be used in court. You want to make a good impression in order to be considered knowledgeable and reliable.

The “never-ending sentence” is a common problem. A sentence goes on and on and on leaving the reader gasping for breath. An example: “I asked the victim if he could identify the robber and before he could answer, he was interrupted by his mother, who was urging him not to say anything because she was afraid that if he answered, he might find himself in harm’s way and end up hurt somehow” (Hart, 2017).  

Whew! Forty-nine words in that sentence. It’s just not an efficient or effective way to communicate. It would be far better to break that sentence down into several shorter sentences. Besides being easier for the reader to digest, it will probably cause the author to omit some of the “fluff” that gets included in such sentences (Hart, 2017).

A corollary to this is to avoid the “never-ending paragraph.” An amazing number of police reports go a full page or more using just one paragraph. Your readers expect a break every now and again. These pauses help the reader comprehend your message in a clear and logical way.

Simplicity proves to be the key to success. Officers encounter trouble when they try to make reports fancy. Intricate writing works for an English class; however, it wastes time and enables errors when writing reports. Police officers must remember that they write to inform, not to impress.  

Audience.  Police reports are often read by other officers, but sworn personnel are not the only people that read reports.  Consider your audience. Use Standard English (not slang, police “ten codes” or “signals”, abbreviations) so that anyone reading the report understands the meaning clearly.

Clarity.  A lot of report writers force the reader to search for information. For example, many officers include the date and time in the heading of their reports. Then they begin their report like this: “On the above date and time…” This causes a disruption in the reader’s flow, because the reader must now look elsewhere to find out which date and time the author is referencing.

Similarly, authors often put the names and addresses of suspects, witnesses, and victims in the heading, assigning each one a number. Then the author continually refers to each person described in the report as “Subject #1” or “Victim #2.” This is extremely confusing and causes lots of searching for the reader. It is better to identify each person by name in the report so that such confusion is minimized. Do not make your reader hunt for information. Make it easy for them to follow your narrative logically and clearly.

It is important to include all relevant actions, statements and observations in your report.  A lack of detail means a lack of clarity.

Always Proofread.  Your computer’s spell checker will not report improper use of a word that is spelled correctly.  Most spell-checkers offer you several options when an unrecognized word is encountered. Typical options would be “Change,” “Ignore” or “Add to Dictionary.” If you accidentally press “Change” when you meant to press “Ignore” – as when encountering a proper name – you could have some disastrous results.

The best way to proofread a report is to give it to somebody else to read. It is always better to have fresh eyes look for mistakes. Encourage them to point out anything that looks wrong or sounds awkward. Then read it yourself and see if you can improve it. One of the best features of a word processor is that mistakes are easily corrected, without having to type the whole thing over.

Accountability matters. Usually, the people in charge determine the level of writing in classrooms and agencies. If they demand quality, the people they are teaching or supervising will slow down, proofread, seek assistance, and submit superior reports. But if those in charge tolerate mistakes and mediocrity, individuals will produce poorly written reports.

Tips for Avoiding Common Errors

Begin sentences with a noun—person, place, or thing. Writing simple, straightforward sentences often eliminates fragments, run-on sentences, dangling modifiers, and other syntax errors.

Do not tolerate “textspeak” (e.g., u instead of you, or omitted capital letters). Refrain from fixing those errors. Return the report to the writer for corrections.

Avoid unnecessary transitions, like upon hearing the gunshot or whereupon she ran out the door. Keep it simple.

Use everyday language, such as I, me, saw, heard, and house instead of this officer, ascertained, or residence.

Resist the temptation to flaunt your skills. Writing extinguish the illumination instead of turn out the light sounds pompous and does not impress anyone.

Remember that possessive pronouns—his, hers, ours, theirs, yours, and its—never use apostrophes. Link its and his and remember to omit the apostrophe when using the possessive form (e.g., he doubled his speed or the car doubled its speed). Never put an apostrophe after the s in its.

Be careful with woman and women. Writers often use women to refer to a single female: I spoke to a women who witnessed the assault, instead of I spoke to a woman.

Use apostrophes only to show ownership (Linda’s car) and omission of letters in contractions (didn’t, couldn’t). Avoid decorating plurals with apostrophes (e.g., I saw bruise’s on Tom’s left cheek).

Develop the habit of using resources—a dictionary, Internet search, or quick question for a fellow officer who writes well.

Narrative Checklist

_____ Narrative clearly states the crime/event that occurred.

_____ Narrative identifies the scene (time and place).

_____ Narrative summarizes the crime/event in chronological order (beginning, middle, end).

_____ Narrative includes details about what was SEEN.

_____ Narrative is factual (objective).

_____ Narrative is of adequate length to tell the “entire story”

_____ Narrative contains correct spelling.

_____ Narrative contains correct capitalization.

_____ Narrative contains correct punctuation and grammar.

Testifying in Court

For many officers, one of the most stressful duties they must perform is testifying in court under both direct examination and cross-examination.  All law enforcement officers, regardless of their rank or assignments, are going to find themselves testifying on the witness stand at some point. Testifying in court may be the most difficult and important task an officer faces in his or her career.  No other assignment subjects an officer and his/her department to more intense, microscopic scrutiny than the officer’s credibility, competency, and conduct in the courtroom.

Be honest.  When testifying in court, your job is to help the criminal justice system with truthful and accurate testimony. You are there to present evidence on behalf of the state or government to win a conviction. Just provide answers to questions that you can.  Do not ever try to make up answers to questions that you don’t know the answer.

Do your homework.  Make sure that you write a good, concise, case report. If you are not good at report writing, check out the reports of other officers who do write good reports. Read those reports and see how they structure their narratives. Learn from them and make adjustments in your reports. Always write your reports from the perspective of a defense attorney. When you are writing your reports, imagine that you are going to be the defense attorney defending this case. If you write your reports with this mindset, you’re going to give the defense attorney less opportunity to work you over on the witness stand.

What would you be looking for when exploring areas to attack? What are the weaknesses in this police report? Don’t lie about anything. Don’t be afraid to admit any mistakes that you have made during the case — nobody is perfect. There is often an issue of police officers overreaching in their efforts to obtain a conviction.

Look professional.  Dress for your court appearance with the same attention to detail you would in going before a promotion board. You should be exceptionally neat—fingernails clean, hair trimmed, clothes pressed, shoes shined. Carry only the essentials—avoid items that jingle, jangle, flash, shine or otherwise distract. Your department policy may dictate whether you wear a uniform or civilian clothes when you testify. Often, on-duty officers will wear a uniform and off-duty officers will wear civilian attire. In state and local courts, you may be armed whether you are in uniform or not. (In federal courts you generally won’t be permitted to wear your firearm into court.) Be aware that some jurors are distracted by the sight of a witness in civilian clothes armed with a gun and carrying bullets, handcuffs, etc. even if they are testifying as a police officer. Discuss this possibility with the prosecutor before your appearance to decide what you should and should not carry.

Establish your competence and expertise.  Look and be attentive. This communicates that you care about being accurate and responsive. Take the time you need to fully understand the question and give the proper response. It doesn’t hurt to appear thoughtful. Organize your thoughts; don’t be hasty.  It’s tempting to add information to your answer that you think helps advance the prosecution’s case. Resist this temptation. This is the prosecutor’s job; let the prosecutor develop your testimony. Don’t jump ahead, don’t anticipate, just answer the question that is asked.

When you elaborate heavily for the prosecution and then are very reserved in your testimony when cross-examined by the defense, you appear biased. This undermines your credibility as an objective reporter of the facts.  Adding extraneous information to your answer opens up other areas for cross-examination.


Trials are serious matters for everyone involved. Refrain from wisecracks and clever remarks. On the other hand, don’t hesitate to laugh at yourself or an unexpected occurrence, if appropriate. Avoid appearing frozen, calculated or completely devoid of emotion.

Keep the jury interested.  Speak a little louder and slower than you think is necessary.  Don’t inject long pauses between words, phrases or sentences but do concentrate on making each word clearly heard and understood.

Maintain your composure.  It’s normal to be nervous and anxious on the stand. You might sweat, shake, have trouble focusing, forget everyone’s name, speak too rapidly, speak in a monotone voice, your voice may involuntarily raise or lower.  All of these symptoms are normal.

Some pointers to help you compose yourself: Sit up straight, but not stiffly. A normal reaction to the stress of being on the stand is slouching in your chair. Don’t let yourself start slouching as it may progress as your testimony continues.

Orient yourself in the courtroom. Look at each of the walls within your vision without turning around. Look at each person or groups of persons in the courtroom.

Mentally prepare yourself for the fact that when you enter the courtroom everyone–jurors, judges, spectators, attorneys, the defendant, the court staff–ALL will be watching your entrance. Stay poised and remind yourself that this is how every witness is viewed. Don’t avoid looking at the judge or jurors; look back at them as you would a person speaking with you.

Don’t look like an advocate for a conviction. Juries can sense when you appear not to be completely neutral.  Defense attorneys will use this against you. As a witness you’re going to be in the spotlight. You’re going to be cross-examined about all the activities you’ve been involved in surrounding the case. Don’t try to get cute or cocky with the defense attorney. You’re not there to try to outsmart a defense attorney, just to present the facts of the case as you know them to be.

Remember you don’t have to have an answer for every question asked. Don’t be afraid to say, “I don’t recall or I don’t remember.” You’re not supposed to remember everything.

A defense attorney is likely to try to show a judge or jury that you can be very aggressive. They will try to get under your skin and get you aggravated. Don’t fall into that trap. It’s a cheap psychological game they are playing with you. Your job on the witness stand is to convince a judge or jury that you are just doing your job, that you don’t have a personal stake in whether or not the defendant goes to jail. Your personal stake is that you did your job and acted professionally.

Your credibility is going to be attacked on the witness stand.  Often, that is all a defense attorney has to work with. It’s important that you understand that our criminal justice system is set-up to be adversarial. Don’t take it personally.  As they say, “You win some and you lose some.“ It’s just a fact of life, accept it, learn from the experience and move on.

If you, as a law enforcement officer, lose your cool on the stand, no matter what kind of case, you lose all credibility with the jury. The jury, as citizens, have authorized you to carry guns and granted you a power and use of force they do not permit themselves. If you cannot control yourself in a courtroom, they are justified in being gravely concerned about your ability to control yourself on the streets, where you are subjected to much greater stress and no one is watching.

Your patience and temper will be sorely tried with interruptions, delays, argumentative questions and attacks on your character. Do not allow yourself to become arrogant, flip, antagonistic, impatient or excited. The worse it gets the greater an opportunity you are being handed to impress the jury with your strength of character, your integrity, your dignity.

Like it or not, as a law enforcement officer, jurors hold you to a higher standard than they do lay witnesses and they expect you to be able to take more abuse on the stand and still remain professional. Be aware that experienced prosecutors know this and may not come to your defense as quickly as they might a lay witness with an objection that the defense is “being argumentative” or “harassing the witness.” Take this as the compliment it is. The prosecutor knows your credibility will shine through such challenges and knows the jury will become frustrated, impatient and finally angry with your attacker.

References and Further Reading

Bennett, W. W. & Hess, K. M. (2004).  Criminal Investigation, 7th Ed. New York: Thompson.

Baltimore City Police Department Academy Report Writing Manual.  Available:

Hart, F. (2017).  10 steps to improve your written police reports.  Available:

McCarthy, P. (2010).  Turning testimony from stressful to successful.  Available:

NORTH CAROLINA STATE BUREAU OF INVESTIGATION.  (2010). Report Writing Manual.  Available:


Modification History

File Created:  05/02/2019

Last Modified:  04/30/2021

[ Back | Content | Next]

This work is licensed under an Open Educational Resource-Quality Master Source (OER-QMS) License.

Open Education Resource--Quality Master Source License


Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Doc's Things and Stuff uses Accessibility Checker to monitor our website's accessibility.