Evidence suppression is the act of having a piece of evidence thrown out—that is, ruled “inadmissible”—in a criminal court case. If your defense attorney feels that a piece of evidence is not legally relevant or competent in your case, he or she may make a motion to suppress that evidence.
In order for a piece of evidence to be admissible in a criminal court case, it must be deemed both relevant and competent.
Evidence must be directly related to the charges at hand in order to be relevant. To qualify as competent, the evidence must have been collected and handled in a lawful manner. This means that your Fourth Amendment protection against unlawful search and seizure must not have been violated in the collection of the evidence.
If a piece of evidence was collected in violation of your Fourth Amendment rights, the Exclusionary Rule should prevent the evidence from being used in court. Further, any evidence that otherwise would have been admissible—including a confession—may be thrown out if it resulted from a Constitutional violation.
The most common reasons that evidence may be ruled inadmissible include: discovery or collection of the evidence by unlawful search and seizure (Fourth Amendment violation); failure of police officers to read Miranda rights to the suspect; and failure to properly document and care for evidence.
If you have been charged with a crime, you should consult with an experienced defense attorney who can examine the evidence collected in your case and ensure that your rights have not been violated.