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Cross-Examination Strategies for Law Enforcement.

Cross-Examination Strategies for Law Enforcement

Courtroom dramas portrayed in the movies or on television often pit crafty defense attorneys against law enforcement officers who seem to have spent their entire careers on the witness stand. Their unimpeachable testimony stands up to grueling cross-examination, and the suspect goes to prison for life.

In reality, over the course of their careers, most law enforcement officers rarely testify during actual trials. Still, when they do, they are considered expert witnesses whose credibility can make, or break, a case. Knowing this, defense attorneys attempt to undermine their credibility by challenging everything from their investigative techniques to their personal belief systems.

These cross-examination strategies are not new. Yet, law enforcement officers routinely stumble on the witness stand because they do not anticipate the defense's questions. Law enforcement officers should consider five general areas before, during, and after investigations to limit the defense attorney's ability to question their findings during cross-examination.


Simply put, in order to enforce the law, officers need to know the law. While they will develop a better understanding of a particular law as a case progresses, officers need a solid foundation from the start. They must know the elements that constitute the law in order to obtain the evidence required to convict the suspect. This may mean, for example, proving that a person accused of driving under the influence was impaired while operating the motor vehicle.

In addition, officers should note the definition and understand the effect of key words found in the text of the law. Some words change the interpretation of a statute. For instance, the law says that officers can use deadly force when faced with an imminent threat. How the courts define "imminent" can mean the difference between justified and unjustified force.

Officers can make a big mistake by confusing two little words: "and" and "or." If, for example, a law contains several elements separated by the word "and," all of the elements must be proven to obtain a conviction. Conversely, the word "or" requires that only one of the elements be proven.

Sometimes, the legal definition of a word differs from its meaning in everyday context. To the average person, the word "shall" is a fancy way of saying "will." In the law, however, it creates a duty for a law enforcement officer to act.

Knowing the law goes hand in hand with understanding its application. Some important constitutional guidelines that dictate how the police gather evidence include search and seizure laws and the Miranda ruling. Officers unfamiliar with the full scope of these restrictions risk seizing evidence or obtaining confessions that will be suppressed later. When in doubt, officers should consult their legal advisors or local prosecutors.

In addition to following the law, officers should adhere to departmental policy. First, department regulations usually reflect the law. Second, failure to follow proper procedures may be grounds to suppress evidence. Finally, defense attorneys try to discredit law enforcement witnesses by emphasizing that they failed to follow their departments' rules.

Every day in the field, law enforcement officers conducting criminal investigations are called upon to make quick legal decisions. These decisions are later scrutinized in the sterile environment of the courtroom. Law enforcement witnesses who display a thorough understanding and well-founded application of the law garner favor with the judge, the jury, and the defense attorney.

Judges give much more latitude and credence to the answers of these officers. Jurors generally find their evidence reliable and credible. And, defense attorneys second-guess their own cross-examination strategies instead of the officers' investigative techniques.


Defense attorneys also may try to discredit law enforcement witnesses by blurring the line between fact and opinion. Usually, they establish the foundation for this strategy during jury selection.(1) A typical dialogue between a defense attorney and a potential juror may go something like this.
 Attorney: Do you know the difference between fact and opinion?

 Juror: Yes.

 Attorney: If I told you that the sun rises in the east and sets in the
 west, is that fact or opinion?

 Juror: Fact.

 Attorney: Correct. If I told you that my best friend was nicer than your
 best friend, is that fact or opinion?

 Juror: Opinion.

This exchange appears innocent but could prove damaging during the trial when the defense attorney discounts the law enforcement officer's testimony as opinion, not fact. This frequently occurs during DUI trials. If the defendant refuses to take Breathalyzer and field sobriety tests, the testimony of the arresting officer may be the prosecutor's only evidence. In such cases, the defense will argue that without corroborating tests, the defendant's condition at the time of arrest is merely the officer's opinion. With the foundation established during the selection process, jurors may find it easy to dismiss the officer's testimony.

Fortunately, officers can mitigate this defensive tactic by adhering to certain principles. First, they should work with the prosecutor during the investigation and while preparing for trial. Such a relationship usually can alleviate most of the pitfalls associated with the fact-versus-opinion defense.

Second, officers must know which statements are facts, which are opinions, and the difference between the two. Distinguishing between fact and opinion becomes particularly important on the witness stand. Although defense attorney's try to cast doubt on officers' observations by labeling them "opinion," judges often admit them as factual evidence, based on officers' training and experience. For this reason, when testifying, officers should state their opinions relating to the case as if they were facts.

Finally, and perhaps most important, even if the defense repeatedly makes them distinguish between the facts of the case and their opinions, officers should remain calm and not become defensive. They should see this tactic for what it is: the defense's attempt to discredit them by making them appear argumentative. And, if the defense attorney is right, officers should not hesitate to affirm this.


When searching for material to use during cross-examination, defense attorneys usually turn to the official paperwork. Law enforcement officers can prepare by reviewing their paperwork from the defense attorney's point of view. In general, all of the information contained in an investigative report can be divided into two categories: objective and subjective.

Objective Information

Objective information includes such verifiable facts as the subject's address, the color of a vehicle, and the date and time of the incident. Based on the belief that it is easier to observe and document objective facts than subjective information, defense attorneys often focus on this area. After all, if officers cannot get the facts right, how can they be trusted to draw accurate conclusions? By calling attention to discrepancies in the officer's report, the defense attorney tries to convince the jurors that they cannot trust the officer's testimony.

Clearly, officers must ensure the accuracy of their reports and never include information that they have not verified. Yet, a defense attorney can trip up even the most diligent officer. For example, defense attorneys know that officers usually estimate time and distance on their reports. After verifying the exact information themselves, defense attorneys will put law enforcement officers on the stand and try to get them to estimate the numbers.

Some defense attorneys use a casual approach to elicit this information. They pretend the exact answer is not important, that the officer should merely guess. More experienced attorneys will bait officers by questioning their ability as well-trained professionals to give accurate answers. Whatever their method, their motives are clear. They want the officer to give an opinion on a fact they have already verified. By doing so, they can contradict and, in turn, discount the officer's testimony.

To avoid these pitfalls, officers should double-check all of the facts and let someone else review them for accuracy. When estimating measurements, officers should write "approximately" in the report. On the witness stand, they should be prepared to explain how they derived these figures. And, when unsure of an answer, officers should simply respond, "I don't know."

When comparing multiple documents, officers should use a checklist to make sure the answers are consistent. The difference between writing 6:01 p.m. on a supplemental report and 6:05 p.m. on the original may seem insignificant, but the defense attorney can be counted on to magnify such discrepancies in court. Because it can mean the difference in the verdict, officers should verify every piece of information, even if it requires an extra phone call or yet another trip to the communication center. Furthermore, officers who spot errors or inconsistencies before or during the trial should bring them to the prosecutor's attention.

Subjective Information

The observations an officer makes at the scene of an incident, such as the demeanor of a DUI suspect or the extent of injuries to a crime victim, constitute subjective information. Unlike the length of a skid mark, this information cannot be measured. Still, during cross-examination, the defense attorney will attempt to create reasonable doubt by showing that several conclusions could have been drawn from the same agreed-upon facts.

Subjective observations can convict criminals. The key is witness credibility, which officers can ensure through accurate report writing.

Yet, "accurate" does not mean "exact." Although it is virtually impossible to generate a written report that exactly captures all of the observations made during an investigation, the defense will try to get officers to say that it can be done. Officers who know the purposes of written reports and can explain them during cross-examination will diffuse the defense attorney's efforts.

The following facts apply to all written reports.

1. They are made at or about the time of an event for investigative purposes, and everything contained in them is accurate to the best of the officer's knowledge at the time it was written.

2. The statements of others reflect what the officer heard at the time, even though someone else might have heard otherwise or witnesses may have changed their opinions since giving their statements.

3. Reports serve as records of events so officers can speak intelligently about them later without having to recall them from memory.

Law enforcement officers can detect when defense attorneys are about to use their paperwork against them. A common method used to accomplish this involves asking several leading questions in a row, counting on the witness to answer "yes" to all of them. The first two questions might be, "You have law enforcement training, right?" and "You learned how to make a report, right?" After getting the witness into the habit of answering "yes," the defense attorney asks a question such as, "You were taught to report everything, right?" or "You were taught to be complete, right?" If the witness answers "yes" now, the defense will point to missing information on the report as an example of the officer's ineptitude. Officers who answer "no" do not fare much better. Their departments come under fire for inadequate training. Either way, the witness loses credibility with the jury.

A better way to approach these types of questions is to answer "yes" or "no" with an explanation.(2) If asked about the completeness of their reports, for example, witnesses should explain that the reports include every possible observation that could be made at the time.

If the judge does not allow witnesses to explain their answers, the prosecution will provide the opportunity during re-direct examination. Sometimes, waiting until later to explain a previous response has distinct advantages. First, by answering only the question asked, the officer looks professional. Second, a viable explanation offered after a few minutes, or in some cases hours, in response to an issue the defense attorney thought was important usually serves to diffuse the situation and reduce the potential value to the defense. Conversely, witnesses who respond by saying they included only the important or relevant facts make the situation worse by provoking additional argument from the defense.


When jurors evaluate evidence, they naturally consider the credibility of the witness. They may not believe witnesses who contradict themselves or do not answer questions in a straightforward manner. Unfortunately, some law enforcement witnesses think they need to win a case singlehandedly. As a result, they may change their testimony to fill in the holes they perceive other witnesses have opened. In doing so, they risk losing credibility.

Moreover, defense attorneys often attempt to prove that law enforcement witnesses hold racist or sexist views that bias their investigations. The O.J. Simpson trial showed what can happen when law enforcement officers harbor these views.

It is assumed that all witnesses, law enforcement or otherwise, take the stand with their own world views. Officers need only admit that their personal views did not affect the investigation. Even if the defense attorney uses leading questions to elicit a prejudiced response, officers should honestly answer "yes" or "no" and offer an explanation.


On television, defense attorneys often call surprise witnesses to clear their defendants. In reality, neither the prosecution nor the defense can put a witness on the stand without the other side knowing about it beforehand. And, fortunately for law enforcement officers, there is no such thing as a "surprise defense attorney." As a result, before the trial, officers can find out who will defend their suspect and, if possible, observe that person in court. If not, they should at least attend a similar trial.

Defense attorneys may differ in style and strategies, but as individuals, they usually use the same techniques and litany of questions to impeach officers. By watching defense attorneys in action, law enforcement witnesses can gather valuable information.


Ideally, cross-examination allows the prosecution and the defense to present to the jury all of the evidence allowable under the rules. Unfortunately, defense attorneys also use cross-examination to create reasonable doubt in the minds of the jurors, and despite predictable actions, they often succeed in tripping up law enforcement witnesses.

Fortunately, officers do not need a crystal ball to predict what questions defense attorneys will ask. Their tried-and-true methods include testing officers' knowledge and application of the law, questioning their observations, casting doubt on their reporting abilities, and attacking the integrity of their work. Armed with this information, law enforcement officers can defend themselves against the most cunning defense lawyer. Indeed, the right time for law enforcement officers to contemplate the defense's strategy is at the beginning of an investigation, not while they are sitting on the witness stand.


(1) Depending on the jurisdiction and the nature of the case, investigators may not be permitted to observe jury selection.

(2) Before replying, witnesses should ask the judge if they can explain the answer they give to the attorney's question.
COPYRIGHT 1997 Federal Bureau of Investigation
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1997, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

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Publication:The FBI Law Enforcement Bulletin
Date:Sep 1, 1997
Previous Article:Crime scene searches: the need for Fourth Amendment compliance.
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