Can Illegally Obtained Evidence Be Used Against You in Court?

Understanding when evidence should be excluded can be crucial for a criminal defense strategy. In this article, we’ll explain how courts determine whether evidence was obtained legally, common scenarios in which evidence is excluded from a criminal case, and when an illegal search can invalidate an entire case.

If you’re facing criminal charges, consider contacting a criminal defense attorney near you. They can help review your case and determine whether law enforcement officers can use the evidence against you. 

How Courts Determine if Evidence Was Obtained Illegally

If police find evidence through methods that violate your constitutional rights, it may be inadmissible in court under the exclusionary rule. This protection does not happen automatically. Your attorney needs to file a motion to suppress before trial, asking the court to exclude the unlawfully obtained evidence.

How much impact getting evidence tossed will have depends on how important it is to the prosecution’s case. For example, if police discovered drugs during an unlawful search of a vehicle, and it’s the only thing supporting drug possession charges, getting it suppressed could lead to a dismissal. If prosecutors have other lawful evidence connecting you to the crime, losing one piece of evidence might just weaken their case rather than end it.

The timing of when you file your motion also matters. In general, you need to file a motion to suppress evidence before the trial begins. Under the Federal Rules of Criminal Procedure, the court can set a deadline for filing a pretrial motion. If it doesn’t, the deadline is at the beginning of the trial. Once that deadline passes, you usually can’t challenge how the police obtained evidence against you. This is another reason having a criminal defense attorney is essential.

Common Scenarios Where Evidence Gets Excluded

Courts exclude various types of illegally obtained evidence. Understanding these examples can help you recognize potential violations in your own case, and include:

• Drug evidence from illegal vehicle searches: You’re pulled over for a broken taillight, but the police search your entire vehicle without your consent or probable cause. They find drugs in your trunk. If the search is ruled unconstitutional, the drugs cannot be used as evidence against you.
• Statements made after illegal arrests: You’re arrested without probable cause. At the station, you make incriminating statements. Because the arrest was unlawful, any statements you made afterward may be inadmissible under the legal argument of “fruit of the poisonous tree.” In addition, statements made without Fifth Amendment protections against self-incrimination may also be excluded.
• Evidence from warrantless home entries: Police enter your home without a warrant, consent, or emergency circumstances (exigent circumstances). The court may exclude any evidence they seize, such as weapons, contraband, or stolen property.
• Weapons found during an unlawful stop-and-frisk: An officer stops and frisks you without reasonable suspicion that you’re armed and/or involved in criminal activity. Any weapon found during this unconstitutional frisk may be inadmissible.
• Cell phone or computer data collected without a warrant: After an incident, the police take your phone and search through messages, photos, or apps without a warrant. Under modern Fourth Amendment law, police officers cannot search through your phone without a warrant. The court may exclude this digital evidence.

Courts consider the totality of circumstances when deciding whether to suppress evidence. A criminal defense attorney will examine how police obtained the evidence and whether they followed the procedures set by the U.S. Constitution.

The “Fruit of the Poisonous Tree” Doctrine: How One Illegal Search Can Invalidate Your Entire Case

The fruit of the poisonous tree is a legal doctrine in criminal law. It likens illegally obtained evidence to the fruit of a tainted tree. If police obtain the original evidence illegally (the “tree”), anything connected to it (the “fruit”) is also tainted and inadmissible. Courts often prohibit prosecutors from using this tainted evidence at trial.

Let’s examine the doctrine with an example. Police arrest you without probable cause. This is the poisonous tree or the initial constitutional violation. While in custody following this illegal arrest, you confess to a crime. This confession may violate both the Fourth and Fifth Amendment protections. This confession is the first fruit. Based on your confession, investigators locate a witness who provides incriminating testimony. This is the second fruit. That witness leads police to physical evidence at another location. This is the third fruit.

Because the original arrest violated your Fourth Amendment rights, they could exclude all evidence that follows. This makes the entire chain potentially inadmissible.

When Illegally Obtained Evidence Can Still Be Used

In general, evidence obtained illegally is inadmissible against you. However, the exclusionary rule comes with certain exceptions. Prosecutors may still introduce unlawfully obtained evidence in certain situations, even when police violated your constitutional rights. Understanding these exceptions is crucial if you’re facing criminal charges.

The following scenarios are examples of when courts allow the use of illegally obtained evidence:

Good Faith Exception

Prosecutors frequently invoke the good-faith exception to keep evidence from being excluded. Even if the warrant was defective, they may argue that the court should still admit the evidence, since the officer reasonably believed it was valid when they used it.

United States v. Leon (1984) addressed this issue. The U.S. Supreme Court ruled that if the police honestly and reasonably believed they were holding a valid search warrant, the evidence obtained from that invalid search could still be used.

The Court noted that the exclusionary rule is present to prevent police misconduct. If officers relied on what they believed was a valid warrant, excluding the evidence wouldn’t deter future misconduct since they were acting in good faith.

Inevitable Discovery Exception

Prosecutors might argue that police would have discovered the evidence anyway through lawful means. The case of Nix v. Williams (1984) ruled on the inevitable discovery doctrine. This Supreme Court case explained that the prosecution can still use the evidence against you even if officers initially found it through an illegal search. Prosecutors must prove by a preponderance of the evidence that a legitimate investigation would have inevitably led to the same evidence, even if no constitutional violation occurred.

Independent Source Doctrine

Prosecutors will sometimes claim that they gather evidence through sources completely separate from any unconstitutional conduct, making that evidence admissible. For the independent source exception to apply, the warrant must be a genuinely independent source of information. This means the officers’ decision to seek a warrant wasn’t based on what they saw during the illegal entry, and that no information from the illegal search influenced the court’s decision to issue the warrant.

Attenuation Doctrine

Prosecutors may argue that too much time passed between the police misconduct and the discovery of evidence, claiming that the connection became too weak to require exclusion. Courts consider factors such as the time elapsed between the violation and discovery, intervening circumstances, and the flagrantness of the police misconduct.

The Supreme Court‘s decision in Utah v. Strieff (2016) expanded prosecutors’ ability to use this argument. In Utah, officers illegally stopped a defendant, but then discovered he had an outstanding arrest warrant. The Court ruled that the warrant broke the connection between the illegal stop and the search that followed the arrest.

Plain View Doctrine

Prosecutors may argue that the evidence was in plain view or in a place that was readily apparent to the officers when they found it. When officers are lawfully present in a location and observe contraband or evidence in plain view, they may seize it without a warrant. They must meet the following requirements for the evidence to be admissible:

• The law enforcement officers are lawfully present at the location
• They must have lawful access to the object
• The incriminating nature of the item must be immediately apparent

For example, officers serving a search warrant for drugs in a house could seize an illegal weapon left in plain sight.

Exigent Circumstances

Prosecutors may also claim that exigent circumstances justified a warrantless search. These are emergencies in which officers need to act immediately or situations in which waiting for a warrant is impractical. This includes instances in which they must prevent someone from destroying evidence or responding to an immediate threat.

An experienced criminal defense attorney can help examine the facts of your case and identify which exceptions could arise. They can help you build your defense or arguments to counter them.

Your Fourth Amendment Rights During Police Searches

The Fourth Amendment protects you against unreasonable searches and seizures. Understanding when police can and cannot search you helps you recognize potential constitutional violations.

Warrant Requirements

In general, law enforcement must obtain a warrant before searching your home, vehicle, or belongings. Valid warrants require probable cause, an approval of a neutral judge, and a particular description of what and where they can search. Police cannot search beyond what the warrant authorizes.

Stop and Frisk

Police may briefly stop and question you if they have reasonable suspicion you’re involved in criminal activity. They can conduct a limited pat-down for weapons if they reasonably believe you are armed and dangerous. Officers should limit this protective frisk to detecting weapons or items that could cause the officer harm.

Vehicle Searches

Officers have greater latitude to search vehicles than homes, but a simple traffic stop doesn’t authorize a complete search of a car. They may search a vehicle without a warrant when they have probable cause to believe it contains contraband. They can also search your car during your lawful arrest, with your consent, or if they observe contraband in plain view.

Home Searches

Your home receives strong protection under the Fourth Amendment. Except in emergencies, police must have either a warrant or your voluntary consent to enter and search. Warrantless home entries are generally unconstitutional unless:

• A resident or someone with authority over the property consents to entry
• Police are in pursuit of a fleeing suspect
• Officers believe someone inside faces imminent danger
• Evidence is actively being destroyed

Even if the police conduct a warrantless search of your home that you think is illegal, don’t interfere or block their efforts. This is a battle to fight in a courtroom, not your living room.

Phone and Digital Data Searches

Police often need warrants to search cell phones and computers, even when seized during lawful arrests. These devices contain vast amounts of private information deserving strong constitutional protection.

How To Challenge Illegally Obtained Evidence in Your Case

The judge will not automatically exclude evidence recovered during a warrantless search. Whether your trial is in federal or state court, your defense attorney must object to the state’s use of this evidence by filing a Motion to Suppress.

A Motion to Suppress must identify the evidence the defendant seeks to have the judge exclude and explain why it is inadmissible. It must also identify the police conduct that led to the discovery of the evidence. The state will then have the opportunity to explain why it should admit the evidence. Once the judge hears both sides, they decide whether to exclude the seized evidence.

Filing a Motion to Suppress Evidence

A criminal defense attorney will prepare a formal written motion filed with the court that identifies each piece of evidence you want excluded. It also explains the constitutional or statutory basis for suppression.

A Motion to Suppress should be filed before the trial begins. In federal court, pretrial motions must be filed within the timeframe set by the judge at arraignment or shortly thereafter. Failure to file before the deadline may result in the waiver of your right to challenge the evidence.

Proving You Had a Reasonable Expectation of Privacy

Courts evaluate suppression motions based on the totality of the circumstances. A key issue is whether the defendant had a legitimate expectation of privacy in the area searched. The location of the search and your relationship to that space matter. Your attorney will analyze the admissibility of evidence and whether the prosecution followed constitutional standards. When judges grant suppression motions, prosecutors cannot use that evidence during trial.

Get Help With Your Criminal Case

The exclusionary rule can prevent prosecutors from using illegally obtained evidence against you, but there may be exceptions. When facing a criminal charge, time is critical. Missing deadlines set by federal or state laws can mean losing your right to challenge the evidence.

An experienced criminal defense attorney can evaluate the evidence against you. They can identify constitutional violations and file the necessary motions on your behalf. You can find a criminal defense attorney near you through FindLaw’s attorney directory.