A motion to suppress evidence is an objection over evidence. The motion should be given to the court before trial begins. The motion challenges evidence on constitutional grounds. Generally a motion to suppress is based on:

  • Fourth Amendment protections against unreasonable search and seizure
  • Fifth Amendment limitations of self-incrimination
  • Fifth and Fourteenth Amendment safeguards for due process

Unreasonable Search and Seizure

The Fourth Amendment to the US Constitution guarantees the right to be free from unreasonable searches and seizures. The amendment requires that search and arrest warrants be approved by a judge and supported by probable cause.


The Fifth Amendment to the US Constitution protects against self-incrimination. It states that no person may be forced to testify as a witness against himself. A confession obtained through harsh interrogation techniques, where the individual wasn’t told about his right to remain silent, may not be admissible in court.

There are five basic things that law enforcement should tell people when they are arrested. These are known as Miranda warnings and they are:

  • The right to remain silent
  • The right to talk with an attorney before being questioned
  • The right to have an attorney present while they are questioned
  • The right to have a court appointed attorney if they cannot afford to hire a private attorney
  • Anything they say can be used against them in court

Due Process

The Fifth and Fourteenth Amendment protect against abuse of government authority. Generally due process guarantees that laws must be written so that a reasonable person can understand what is considered criminal behavior.

Purpose of a Motion to Suppress

The purpose of the motion to suppress is to ask a judge to exclude certain evidence that was improperly obtained. This is true even though that evidence may be relevant and highly incriminating.

Motion to Suppress Procedure

The defense attorney starts the motion to suppress evidence process by filing formal papers with the court before a trial begins. The prosecutor and defense counsel submit legal arguments in what is known as a brief. If there has been an arrest, the prosecutor files the first brief. The prosecutor’s brief states the reason for each step taken by the police. The defense attorney responds with a brief explaining how the police violated the defendant’s constitutional rights.

Typical Challenges

A suppression motion typically challenges such things as:

  • Illegally seized evidence
  • Improperly obtained confessions
  • Results of chemical tests administered to determine blood alcohol content
  • Whether police had probable cause to make a traffic stop or arrest

Motion to Suppress Hearing

A motion to suppress hearing is a court appearance where both sides can argue about whether evidence against a defendant should be thrown out because the defendant’s constitutional rights were violated.

Waiver of Objections to Evidence

A defendant’s failure to make a pretrial motion to suppress evidence is considered a waiver of any objection. This means that during trial the defendant may not object to the admission of the evidence on the ground that the evidence was unlawfully obtained.

Judge’s Ruling

Evidence must be suppressed if its exclusion is required by the federal or a state constitution.


A judge’s ruling denying suppression of evidence may be appealed.

Questions for Your Attorney

  • When can a motion to suppress evidence be filed?
  • May a judge wait until the trial begins to rule on a motion to suppress?
  • When must evidence be suppressed?
  • What is the difference between a motion to suppress evidence and a motion in limine?

The information provided above is a very general summary of motion to suppress law at the time this text was prepared. Because this analysis is subject to change depending upon recent cases and legal developments, you should not rely on this summary as legal advice. As with any important legal question, you should always consult a lawyer experienced in criminal defense and licensed to practice in your jurisdiction. Brett L. Grayson is licensed to practice in all federal and state courts in Louisiana and may practice in other federal courts by special permission.