Filing a motion to suppress evidence is a legal action in which a defendant asks a judge to prevent certain evidence from being used in a court case. It is only applicable in cases where the defense team believes, and can prove, that evidence was collected unlawfully or that proper police protocols were not followed. A motion to suppress must be written and formally submitted to the judge for approval or denial. It is often used in jury cases to prevent jurists from ever hearing about certain pieces of evidence. However, suppression motions can also be used in cases decided only by a judge.
A motion to suppress is filed before the trial even begins so that there is no chance of tainting a jury with illegal evidence. Once the defense attorney submits a formation motion to suppress, the prosecutor prepares a brief explaining why the evidence should be admitted. The defense then prepares their brief explaining why the evidence should be suppressed. A hearing is scheduled to decide on the motion which gives both sides the opportunity to present oral arguments. If the presiding judge decides to reject the motion for suppression, the defense can file an appeal.
Reasons for Suppressing Evidence
A motion to suppress can be based on violations of the U.S. Constitution, a state constitution or a federal or state statute. They are most commonly filed due to violations of the 4th, 5th and 14th Amendments. In addition to suppressing evidence that was unlawfully or wrongfully handled, these motions can suppress evidence that is not pertinent to the case being tried. For example, if a suspect is on trial for manslaughter but the police found the weapon without a search warrant, the weapon is not admissible as evidence. This instance would fall under the unlawful search and seizure rule. The defendant will still be tried, but no evidence can be presented about the weapon.
Another example would be if a suspect confessed to a crime prior to being read Miranda rights. That confession is illegal and cannot be used against him in a court of law. Chain of custody errors are another common reason to suppress evidence. This occurs when items such as blood work or drugs are mishandled in some way during the booking or analysis process. Because the court cannot prove they weren’t tampered with, the evidence is suppressed and cannot be legally used.