A motion to suppress seeks to exclude illegally obtained evidence based upon a constitutional violation. The purpose of a motion to suppress is to determine, before trial, whether particular evidence will be admissible at trial. If the judge finds the evidence is not admissible, the prosecuting attorney may determine they cannot go forward on the case and dismiss it entirely. If the judge rules the evidence is admissible, the defendant may be more inclined to enter a guilty plea knowing the objected to evidence will be admitted.
A motion to suppress must:
- Be made in writing
- Raise a constitutional ground or basis
- Allege sufficient facts to place the prosecution on notice of the claim of unlawfulness
- Be filed no later than 10 days after arraignment (unless judge allows for extension in writing)
A failure to comply with these requirements could result in a waiver of your motion and ability to resolve these issues before a trial.
Once a motion to suppress has been filed, the burden of proving the lawfulness of the legal issues raised is placed on the State. A defendant is general entitled to an evidentiary hearing unless the parties agree to the facts. If so, the judge may rule on the motion without a hearing as a matter of law. The hearing must occur outside the presence of a jury.
For example, in the context of a DUI case, a defendant should file a motion to suppress the results of a chemical test (ex. breath or blood) if there was insufficient probable cause to arrest. The prosecutor would have to call the arresting officer to court and prove to a judge there was probable cause to arrest. Not only could a judge rule in your favor, but a defendant also receives the benefit of officer testimony made under oath. Therefore, if the officer later testifies at trial to something inconsistent with what that officer said at the motion to suppress, the officer’s prior inconsistent statement could be used to impeach that officer (showing they are not credible).
 A motion to suppress does not apply to (1) attacks on the validity of charging documents (accusations or indictments); (2) chain of custody issues; or (3) to testimony.