In many criminal cases, the most important litigation comes before the trial. The Commonwealth bears the burden of establishing the evidence it intends to use against the defendant was obtained in a lawful manner. A defendant who claims any of the evidence was obtained by way of police misconduct or coercion will file a motion to suppress that evidence.
When a defendant files a motion to suppress, the judge will schedule a hearing. At the hearing, the Commonwealth bears the burden of proving the evidence was obtained legally. The hearing is usually evidentiary, which means the prosecutor will call witnesses to testify about how the evidence was gathered. The defense has the right to cross-examine the Commonwealth’s witnesses and call its own witnesses. After the witnesses have testified, the attorneys are entitled to make legal arguments to the judge. The judge will either make a decision immediately or take the motion under advisement. A motion is taken under advisement when the judge needs to perform additional legal research before making a decision.
What happens if the judge concludes the police gathered the evidence in an unconstitutional manner? In most cases, the evidence is excluded from trial, which means the prosecution cannot present the evidence to the jury. Oftentimes the exclusion of the evidence means the prosecutor needs to dismiss the case. Suppose, for example, the police search a defendant on the street and discover he is illegally carrying a gun. If a judge rules the search of the defendant was unconstitutional, the gun will be suppressed and excluded from trial. Because the Commonwealth cannot introduce the gun into evidence at trial, it no longer can prove a crime and the case will be dismissed. Sometimes the Commonwealth will be able to continue the prosecution even if some of the evidence is suppressed, but its case will usually become considerably weaker. For example, if a defendant’s confession to a crime is suppressed, the government can still try to prove guilt with other evidence.
A defendant can file a motion to suppress any type of evidence that has been obtained by the police.
Anytime police officers conduct a search, either with or without a warrant, their conduct is governed by the federal and state constitutions. If a police department oversteps its authority and searches in an unconstitutional manner, the physical objects it seizes are subject to suppression.
If police officers ask the victim of a crime to pick the defendant out of a lineup or a photo array, the officers are not permitted to assist the victim in identifying the defendant. If the lineup is unduly suggestive, the defendant’s identification is subject to suppression.
Police officers always try to convince defendants to admit to committing crimes. In some cases police officers are required to provide Miranda warnings to the defendant and if they fail to do so, the defendant’s statement is subject to suppression. Even if a statement was given to someone other than a police officer, the government must prove that the statement was voluntarily made.
The “fruit of the poisonous tree” doctrine states that any evidence obtained as a result of illegal police conduct will be subject to suppression. Suppose the police illegally search a defendant’s car and discover contraband. The contraband in the car constitutes probable cause to believe additional contraband will be found in the defendant’s home. The police obtain a search warrant for the defendant’s home and find the additional contraband inside. Because the police learned about the contraband in the home as a result of the illegal search of the car, the evidence found in the home (as well as the car) will be suppressed as fruit of the poisonous tree.