How Does Evidence Get Suppressed?

Barnes & Fersten Law Firm

Barnes & Fersten Law Firm

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Evidence plays a critical role in any criminal trial. It can be the difference between a conviction and an acquittal. However, evidence can be suppressed for a variety of reasons. Evidence may be suppressed if it was obtained illegally or if it is not relevant to the case. Evidence may also be suppressed if it is unfairly prejudicial to the defendant. In this blog, we will detail how evidence can be suppressed and explore some of the most common reasons for suppression. An experienced criminal defense attorney will know how to identify when evidence should be suppressed and can help you build the strongest defense possible for your case.

Evidence In Criminal Cases

To get a criminal conviction at trial, a prosecutor must present enough evidence to convince a judge or jury that the defendant is guilty of the specified offense beyond a reasonable doubt. Because this is the highest burden of proof in the U.S. justice system, it often requires a substantial amount of evidence to meet. Law enforcement can provide evidence from investigations and the prosecutor can present the evidence in court.

There are several types of evidence that may be used in a criminal case. The four primary types of evidence are:

  • Demonstrative evidence: This type of evidence is used to help explain other types of evidence. It can include items like photographs, maps, and models.
  • Documentary evidence: This is evidence that comes in the form of documents, such as police reports, medical records, and financial records.
  • Real evidence: This is evidence that can be touched or seen, such as weapons, drugs, and DNA evidence.
  • Expert testimony: This is testimony from experts who can provide opinions on specific topics, such as DNA analysis or ballistics.

This is not an exhaustive list of all of the forms of evidence that may be available in a criminal case, but it gives you a general idea of the types of evidence that may be used. Additionally, evidence for criminal cases can come in many forms, including:

  • Physical objects
  • Photographs
  • Witness statements
  • Video or audio recordings
  • Digital data
  • Scientific findings


The law in the United States does not allow all types of evidence to be submitted in court against a defendant, however. There are many protections for defendants in place and rules of evidence that dictate when evidence can be lawfully obtained and presented in court. When illegal evidence comes against a defendant, it can often lead to a wrongful conviction. For this reason, it is imperative to have a highly skilled criminal defense lawyer handling your case who knows how to get evidence “suppressed.”

How To File A Motion to Suppress Evidence

The suppression of evidence occurs when a judge rules that certain evidence should not be submitted at trial. In order for a judge to rule on such an issue, a lawyer must often file a motion with the court asking for a ruling. A motion to suppress is the catalyst that can lead to the keeping evidence out of your criminal case.

In order to succeed on a motion to suppress, your attorney must present sufficient factual information and apply specific laws to those facts to convince the judge that the evidence is illegal. Law presented in these motions can include case law, state or federal rules, or often, the Constitution of the United States. These motions must be persuasively drafted with sound legal analysis and reasoning.

The prosecution can respond to your motion to suppress with their own arguments in favor of the evidence. In some cases, the court will hold a motion hearing during which both parties will argue their case. The judge will then rule on whether the evidence should be suppressed or not.

The Importance Of Evidence Suppression

Often, the suppression of the right evidence can lead a jury to acquit you at trial, or even to the dismissal of charges before a trial ever happens. A common example happens in drug-related cases. In order to convict you of drug possession, the prosecutor must usually prove that police found a controlled substance. They cannot simply tell the jury you had cocaine – instead, they should have the evidence tested and present test results as proof that the substance in question was cocaine.

If police officers obtained the drugs unlawfully – which is more common than you may imagine – a defense attorney can file a motion to suppress the illegally-obtained drug evidence. If the motion is successful, the prosecutor can no longer use that drug evidence to prove that you possessed drugs. This is often the main piece of evidence in drug cases and without it, the prosecution usually knows it cannot prove the drug charges beyond a reasonable doubt. Therefore, they may often dismiss the charges then and there. This is only one of many examples of how the suppression of evidence can prevent a conviction.

Common Reasons To suppress Evidence

As part of the discovery phase of a criminal case, your attorney will obtain and analyze all the evidence the prosecution plans to use against you and how the evidence was obtained. An experienced attorney should be able to identify when there is reason to file a motion to suppress.

Some examples of evidence commonly suppressed include:

  • Evidence obtained by an unreasonable search in violation of your Fourth Amendment rights
  • Evidence obtained due to an unlawful traffic stop or arrest, which constitutes an unreasonable seizure in violation of your Fourth Amendment rights
  • Confessions obtained without proper Miranda warnings in violation of your Fifth Amendment rights
  • Confessions obtained by coercion or physical force
  • Evidence that constitutes hearsay without a valid exception under the Federal Rules of Evidence
  • Evidence that is not relevant to the case at hand
  • Evidence that is unreasonably prejudicial to the defendant
  • Evidence that is not reliable

Significantly, there are countless nuances and legal issues that may result in a suppression for the reasons listed above. For example, an unlawful traffic stop or arrest may occur in countless different ways. The officer may have extended the stop without reasonable suspicion and found evidence to convict you illegally thereafter. The officer may have extended the stop based on your criminal history alone, an anonymous 911 call, among countless different reasons, all of which must be reviewed and scrutinized closely by a skilled criminal defense attorney that will use that information to negotiate a favorable plea agreement or suppress the evidence, potentially resulting in a dismissal of your case, through a motion to suppress.

Hiring a lawyer that knows the caselaw and what to look for could make a huge difference in your case because they will immediately spot the issue when they observe the body camera evidence or discuss the issue with you. For example, caselaw dictates that if an officer searches your vehicle after placing you under arrest as an inventory search, meaning they search the vehicle before towing it to ensure nothing is stolen from the vehicle, the officer must first ask you if you can make your own arrangements to move your vehicle. The reasoning is simple, an officer cannot use an inventory search to get around the search warrant requirement. Thus, if an officer fails to ask you if you want to make your own arrangements, any illegal drugs or evidence found in the vehicle is subject to suppression. However, evidence is not suppressed unless your lawyer files a motion requesting the evidence to be suppressed and consequently, if your lawyer does not know the law, he or she may not know the legal issue exists.

Our lawyers routinely attend continued learning education classes across the nation to stay up to date on legal issues so they know exactly what to look for when reviewing a case to suppress any and all evidence potentially suppressible. Similarly, our lawyers constantly review the new caselaw and watch bodycam footage closely to ensure they do not miss a single issue. Many times, the threat of filing a motion in itself, that may or may not be successful, will lead to a much more favorable plea offer.

The question of reliability often arises in criminal cases, as prosecutors often try to admit evidence based on questionable science. This can include evidence involving fingerprints, bloodstain patterns, eyewitness identifications, or DNA. For example, for decades, many people took the witness stand and claimed they were “experts” in analyzing blood spatter and giving their opinion on how the crime occurred. However, in recent years, scientific studies have cast substantial doubt on the reliability of blood spatter analysis and claim such “experts” led to many wrongful convictions. In this day and age, defense attorneys regularly question a prosecutor’s blood spatter testimony and seek for it to be suppressed.

In addition, defense lawyers know that forensic labs can make many mistakes that lead to unreliable testimony. This is common in DUI cases in which a blood test showed a defendant had drugs in their system or a blood alcohol content (BAC) over the legal limit. Labs may mislabel or switch samples, store them improperly, fail to record results right away, use uncalibrated testing equipment, and make many other mistakes that should render their testimony and the test results unreliable for admission at trial.

Contact A Knoxville Criminal Defense Attorney For Help Today

There are many, many other types of evidence that should be suppressed from criminal trials. The problem is that unrepresented defendants often do not realize when evidence against them is unlawful or how to go about getting it suppressed. Suppressing key evidence is only one of many defense strategies we regularly pursue at Barnes and Fersten Law. If you were arrested or face criminal charges, you should not wait any longer to call a skilled Knoxville defense lawyer for a free consultation. The sooner Barnes & Fersten starts working on your case, the sooner we can start building the most effective defense strategy for you.

Attorney At Law, Managing Partner

Brandon D. Fersten is an esteemed Knoxville attorney practicing DUIcriminal defense, and juvenile law. Known for his empathetic approach and commitment to his clients, he brings a record of favorable case outcomes including dismissals and not guilty verdicts at jury trials resulting in Brandon being recognized as one of the “Top 40 Under 40” in Criminal Defense, U.S. News’ Best Lawyers: “Ones to Watch,” and Super Lawyers’ “Rising Stars”. Brandon’s professional accolades, combined with his passion for justice, position him as a reliable criminal defense advocate in the East Tennessee legal landscape.