Affidavit Writing Made Easy:

Create an Outstanding Warrant Application Every Time

By Michelle M. Heldmyer

Attorney-Advisor (Instructor), FLETC ALGi

Even for the most experienced law enforcement officers, writing an 

affidavit can be a daunting task. Ensuring your affidavit is legally 

sufficient, organized, easy to read, and even interesting, is 

challenging in the best of circumstances. The undertaking is often 

compounded by time constraints and the demands of prosecutors 

and judges. But with simple guidelines and a few easily accessible 

tools, every prospective affiant can create an impressive warrant 

application.

The Basics

Every search and arrest warrant application is governed by rules. 

The primary rule is found in the Fourth Amendment to the U.S. 

Constitution: each warrant requires probable cause, supported by 

oath or affirmation, and particularity. More specific rules governing 

warrants are located within each jurisdictions’ rules of criminal 

procedure. Affiants need to be familiar with those rules, as they 

govern every stage of the process, from content to issuance to 

service of warrants.

To satisfy Constitutional and procedural requirements, warrant 

applications are accompanied by affidavits, designed to satisfy the 

court that the evidence in the case is sufficient to establish 

probable cause. The affiant swears or affirms the provided 

information is true and correct. Affidavits can, and usually do, 

contain hearsay information, because generally the rules of 

evidence do not apply. They can, and usually do, contain supportive 

information from multiple sources, including other officers and 

agents, documents, forensic examinations, expert analysis, 

witnesses, victims, and the affiant’s training and experience.

Affidavits do not need to contain all information known by the 
affiant – they need only reach the level of probable cause to support 

the request. Probable cause only requires a fair probability, given all 

the facts and circumstances provided in the affidavit, along with the 

training and experience of those contributing to the affidavit, that 

evidence will be found (for a search warrant) or the subject 

committed a crime (for an arrest warrant).1

Every request for a warrant is made in furtherance of a criminal 

case, which means criminal statutes are involved. Because an 

affidavit must contain proof of the violation of at least one 

particular statute, knowledge of that statute is imperative. Do not 

assume knowledge of what the statute says. Read it. 

After reading the statute, the affiant will need to know its elements. 

The best source of this information is the criminal jury instructions 

book in your jurisdiction. Most are available online. They are 

written plainly, for an audience with no legal experience, and are 

easy to understand. More importantly, the elements specified in the 

jury instructions tells the affiant what evidence is relevant and 

necessary to support a finding of probable cause.

Building the Affidavit

Having identified your offense elements and verified you have 

enough evidence in support of each and every element to obtain a 

warrant, outline the affidavit. Arrest warrant affidavits are 

commonly more concise and less detailed than search warrant 

affidavits because they are usually followed by an additional 

probable cause finding, like a preliminary hearing or grand jury 

presentment. But both types of affidavits require the affiant to 

establish probable cause, so the basic purpose and structure are

the same.

Each paragraph should be numbered and the document formatted 

to your court’s specifications, if any. A solid basic structure can 

look like this:

 1 Illinois v. Gates, 462 US 213 (1983)
1. Affiant’s name, title, experience, jurisdictional authority.

Emphasize training, experience and knowledge relevant to the 

type of crime named in the warrant. Remember, training and 

experience add to probable cause.

2. Statutory violations involved in investigation and other relevant 

legal citations (i.e., definition statutes, regulations, authority).

3. Statement of purpose of affidavit. “This application is 

submitted in support of my request for the issuance of a 

search warrant for the residence located at 1234 Main Street, 

Anytown, State.”

4. Overview/summary of investigation. The more complex the 

investigation, the more important this “executive summary” 

section becomes.

5. Statement of probable cause. “This affidavit establishes

probable cause to believe evidence of controlled substance 

distribution, in violation of 21 USC 841(a)(1)&(b), will be found 

at the residence located at 1234 Main Street, Anytown, State” 

or “there is probable cause to believe James Blow committed 

the offense of controlled substance distribution, in violation 

of...”

6. Statement of limited presentation of facts. “This affidavit does 

not include all of the facts known to me, but only those facts 

relevant and sufficient to establish probable cause.”

7. Definition section, if necessary. Include definitions if you need 

to use special terminology in the affidavit. 

8. Facts, to include support for each and every element of the 

offense or item to be seized (addressed next).

9. Conclusion. Tie the facts together, and ask for what you want.

Much of the content of most affidavits is standard (“boilerplate”) 

language and can be reused in multiple affidavits. For example, 

affiants can create one basic paragraph about themselves and their 

training, experience, and jurisdictional authority, then simply tailor 

it for each case. Also, certain types of affidavits should contain 

specialized information which can be taken from other similar 

affidavits. Computer searches, child pornography investigations, 
and complex fraud cases, for instance, contain established 

language which the affiant can obtain and insert into the affidavit.

The prosecutor will have access to much of this standard language.

The Department of Justice (DOJ) is another resource. The 

Computer Crimes and Intellectual Property (CCIPS) and Child 

Exploitation and Obscenity (CEOS) Sections of the DOJ, along with 

several other special DOJ sections, can provide advice and warrant 

language.

The Facts Section

Armed with knowledge of the applicable statutes and an outline of 

the affidavit, build the facts section. Most are written 

chronologically, but this style is not required if another is more 

effective. Background information offered prior to the pertinent facts 

can be helpful for context, but less is better. Do not presume 

knowledge of any fact or technical subject, and even some legal 

issues should be spelled out clearly.

If you have exculpatory information or information discrediting any 

of your sources of facts, consult with the prosecutor about whether 

to include it in the affidavit.

Facts included in an affidavit must be attributed to their source. 

The court must determine the credibility of the information, and 

cannot do so without knowing from where it came. If using 

informants, names can be withheld, but information about their 

credibility and the basis of their knowledge is important. Also, if you 

are “cutting and pasting” from other reports, proofread carefully to 

smooth out transitions and to remove repetitive or sensitive 

information.

Active voice is usually preferred over passive voice. Say, “Officer 

Jones interviewed witness Cheryl Adams” rather than, “Cheryl 

Adams was interviewed by Officer Jones.”
The use of the term “Your Affiant” to refer to the writer is common 

but archaic. Consider the simpler version; just call yourself “I” 

instead.

Certain types of information should be avoided in the facts section:

1. Discredited information. If information or its source has been 

found to be unreliable, do not include it. 

2. Argument. Affiants should appear objective throughout the fact 

section.

3. Conclusory statements. Avoid references such as, “we 

investigated, and determined this...” or “a confrontation 

occurred and a struggle ensued.” Include factual descriptions 

and attribution instead: “According to witness Smith, Jones 

ran toward Harris and demanded money. Immediately 

thereafter, Harris grabbed Jones’ arm and pulled Jones to the 

ground.”

4. Repetitive statements. Say it once and move on.

5. Police jargon. For example, avoid use of military time or terms 

like “BOLO.”

6. Technical terminology. If you must use it, define it accurately. 

7. PII. Personally identifiable information (“PII”) could potentially 

become part of the public record, so avoid it if possible. Courts 

are becoming accustomed to references such as “year of birth 

1985” or “date of birth x/x/1985.” If PII must be used, be 

prepared to redact it prior to any disclosure of the affidavit.

Courts usually have redaction procedures in place.

Conclusion

Writing an affidavit need not be difficult. Once you have read the 

statutes and rules, and become familiar with all the facts of the 

case, the pieces will fall into place. Get organized, find time to write 

uninterrupted and get to work. Remember your best resource is 

always your prosecutor.
i Ms. Heldmyer has been a Legal Instructor at FLETC Artesia for 2 years. Before joining FLETC, 

she served 26 years as an Assistant United States Attorney in Colorado and Florida.