Probable Cause Searches: Legal Definition, Standard, Law, and Example

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 Why Does Probable Cause Matter?

“Probable cause” is the level of suspicion needed before police can conduct a search or investigation. The principle behind the standard is to limit the power of authorities to perform random or abusive searches and to promote lawful evidence gathering during criminal arrest and prosecution.

The standard applies to personal or property searches and arrests. The term comes from the Fourth Amendment of the United States Constitution, which protects people from searches and seizures if the arresting officer does not have probable cause.

What Is Probable Cause?

Probable cause refers to the reasonable belief that an individual will commit or has committed a crime or other violation. For a reasonable belief to exist, there must be factual evidence supporting the appropriateness of the search.

Generally speaking, probable cause requires more than a mere suspicion that a suspect committed a crime but does not have to be enough evidence to prove that the person is guilty of a crime beyond a reasonable doubt. The belief must be based on factual evidence, not simple suspicion.

A common example is when a police officer pulls someone over on the highway because the officer suspects the driver is under the influence of alcohol. If the driver is swerving, speeding, braking suddenly, or driving erratically, that would be sufficient evidence to give the police officer probable cause that the person is driving under the influence. The police can then pull over the suspect based on their driving behavior. However, if the driver is driving normally and obeying all traffic rules, the police cannot pull the person over for drunk driving. They have no probable cause to believe that the person is driving while drunk.

What Are the Sources of Probable Cause for a Search of a Person or Property?

Police do not need a warrant to search a car if they have probable cause. This is because getting a warrant would take too long, and the driver would likely simply leave the scene. This is also true if the police see a crime being committed before their eyes – they do not need an arrest warrant. These are called “exigent circumstances.” People arrested without a warrant are required to be brought before a judicial authority shortly after their arrest so that a prompt official determination can be made about whether there was probable cause for the arrest.

Police may also search any place when the person does not have a “reasonable expectation of privacy.” The most common example is using police dogs at the airport to sniff out drugs. The airport is a large public space, and no one has a reasonable expectation of privacy there.

On the other hand, to search a home, an officer must obtain a search or arrest warrant because the homeowner has a reasonable suspicion of privacy in their home. To do so, the office must prove probable cause to a judge or magistrate and ask for a search warrant or arrest warrant to be issued. In general, the court that is issuing the warrant employs a test designed to determine whether probable cause exists.

This test is based on whether an objective person of reasonable intelligence would believe that the circumstances indicate that the person arrested or detained has committed or is in the process of committing a crime.

An officer may rely on four general categories of evidence to establish probable cause. Evidence from any of these four categories would most likely allow an officer to perform a lawful arrest or perform a search:

  1. Any information that an officer obtains through personal observation may be used to establish probable cause. This includes anything within an officer’s “plain view” or anything else based on what an officer sees, hears, smells, or feels.
  2. Circumstantial Evidence: Additionally, an officer may rely on indirect evidence that implies something has occurred but does not directly prove it. An example of this would be how an officer responding to a robbery may have probable cause for arresting or searching a person found to be hiding in an alleyway or running away from the scene with bags in hand.
  3. Expertise: An officer may use their expertise and training to identify certain movements, gestures, preparations, or tools as tending to indicate criminal activity. An example would be how an officer may use their expertise on drug paraphernalia to establish probable cause that the items may have been used concerning drug crimes.
  4. Information: An officer may use information obtained from reliable sources to establish probable cause. Such information could include statements by witnesses, victims, or informants.

It is important to note that a person may consent to search their person or property, in which case probable cause is automatically created. However, the search area is limited to the specific area where permission was given. Permission to search a home may not include permission to search a garage.

And, in circumstances in which a roommate or other resident gives consent to search a home, an officer may not search places that the person who gave consent would not ordinarily have free access to (e.g., a roommate’s private bedroom).

Is Probable Cause the Same as “Beyond a Reasonable Doubt”?

While the two concepts are related and often interact, they are different. Police need “probable cause” – something less than proof but more than mere suspicion – to conduct a search or make an arrest. Once a case goes to trial, the defendant must be proven guilty “beyond a reasonable doubt.” This is a fairly high standard to meet and is instituted to help protect criminal defendants. This is the level of proof required to show that the defendant is indeed guilty.

To clarify: “probable cause” is the level of evidence needed before police can conduct a search or investigation, whereas “beyond a reasonable doubt” is the level of proof needed in criminal trials to find a defendant guilty.

What Happens if the Police Did Not Have Probable Cause?

If the police do not have probable cause to search, any criminal search of the person’s body, belongings, or property will be deemed unreasonable. Evidence directly obtained from a search, seizure, or arrest that occurred without probable cause cannot be used in court against a defendant charged with the commission of a crime.

As such, if a search or arrest was made with or without a warrant, and probable cause was not sufficiently established, the evidence obtained without probable cause may be suppressed in court. It is as if the evidence never existed.

Should I Contact a Lawyer if I’m Facing Issues Involving Probable Cause?

If you do not believe an officer had probable cause to search you, you should immediately consult a well-qualified and knowledgeable criminal lawyer in your area.

An experienced criminal attorney will be able to inform you of your legal rights and defenses to the search or arrest. An experienced and local criminal defense attorney can also represent you in court as needed.

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