A motion to suppress is a formal request to a judge to exclude a piece of evidence from a criminal trial. The defendant, or his or her attorney, may file a motion to suppress evidence if it is believed that the evidence was obtained illegally or in violation of the defendant’s rights. Generally, the motion to suppress is filed ahead of the trial date; if the judge grants the motion, the case could be dismissed altogether.
Motions to suppress are commonly filed in cases involving Fourth Amendment rights. The Fourth Amendment guarantees protection from unreasonable searches and seizures.
Usually, law enforcement officers must obtain a warrant before conducting searches of any kind, although there are circumstances in which an officer may conduct a search without a warrant. In these situations, the officer must be able to justify the search based on the legal standards of reasonable suspicion or probable cause.
Reasonable suspicion is a standard by which an officer may detain and question—but not arrest—an individual. If the officer has a basis to believe that the individual is armed, reasonable suspicion also grants authority to conduct an over-the-clothes pat-down to check for weapons. If a weapon is found, then the officer may have sufficient probable cause—a higher standard than reasonable suspicion—to conduct a full-blown search of the individual. If the search reveals contraband or evidence of criminal activity, an arrest may be made.
It is easy to see why motions to suppress are so common in these types of cases; if a defense attorney can challenge the initial evidence—and therefore the reasonable suspicion cited by the arresting officer—the prosecution’s entire case can unravel before ever going to trial.