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What is Probable Cause?

If the police perform a search without probable cause, it violates the Fourth Amendment.

When a search or arrest violates the Fourth Amendment, corrective action can be taken by the court upon a motion by a criminal defense lawyer. 

Some remedies provided by courts to criminal defendants whose Fourth Amendment rights were violated include: 

  • Suppression of physical evidence
  • Suppression of incriminating statements
  • Dismissal of a case
  • Releasing the accused from custody

You have the right to not be searched or arrested unless the police had probable cause giving them lawful authority to do so.

Defining Probable Cause in Phoenix Arizona 

Defining Probable Cause in Phoenix Arizona People frequently use the term “probable cause” in Arizona but few actually understand what this concept means. This is because probable cause does not have a very clear, concise dictionary definition.  

Probable cause describes the level of suspicion law enforcement needs to perform a search or make an arrest. It is more than a hunch.

Rather, it requires a reasonable belief that:

  • A crime has been committed; or that
  • Evidence of a crime is present in the place to be searched

This definition leads to more questions. When do the police have enough facts that they have a reasonable belief constituting probable cause? This is a judgement call that requires discretion. Basically, it is probable cause if a judge says it is.

Types of Probable Cause

Types of Probable CauseA judge will determine if probable cause exists based on their knowledge of past cases (precedent). Whether for a drug offense, robbery, or assault, the judge will expect to see factual information from law enforcement that makes it reasonable for them to believe a crime was committed by that person or that evidence of a crime is in that place. 

The main types of probable cause are:

  • Probable cause to arrest
  • Probable cause to search a car
  • Probable cause to search a residence
  • Probable cause to continue criminal proceedings

Each type of probable cause has a large body of case law describing what level of suspicion the police need to take the desired action.

Probable Cause to Make an Arrest in Phoenix Arizona

Arrests in Arizona can be made in one of two ways.

First, they can be made with an arrest warrant signed by a judge.

Second, an arrest could be made without a warrant by a police officer in the field who believes they have probable cause to arrest. 

Probable cause to arrest means law enforcement has a reasonable belief, based on the totality of the circumstances, that this person committed a crime.

Examples that could create probable cause to arrest include:

  • The officer saw you commit a crime
  • Eyewitnesses saw you commit a crime
  • An arrest warrant signed by a judge

An arrest warrant is a legal document to arrest a specific person based on a specific crime. Arrest warrants are not valid unless they are signed by a judge. The police will write up all the facts that they believe create a reasonable belief, then take this to a judge to sign. 

A judge then reads all the information provided by the police and decides whether they agree that probable cause exists. If the judge agrees probable cause to arrest exists, they sign the warrant and the police have a lawful warrant. 

Regardless of whether an arrest was made with an arrest warrant, or based on the police making a decision in the field, probable cause is a requirement to a lawful arrest. After an arrest, the law requires you to be promptly brought before a judge for a determination of probable cause for the state to continue to hold you and press charges. 

An arrest or warrant is unlawful if it lacks probable cause.

Evidence that was obtained only due to the unlawful arrest, like an incriminating statement during interrogation, could be deemed “fruit of the poisonous tree,” which means it is excluded from all court proceedings. Physical evidence obtained in a “search incident to a lawful arrest” can be thrown out if it is later determined that the officer lacked probable cause to arrest you. This can make or break an entire case!

What Is Probable Cause To Perform a Search in Phoenix?

Privacy rights in Phoenix under the Fourth Amendment only apply to private areas in which you have a reasonable expectation of privacy.

In general, the government needs probable cause to search:

  • Your residence
  • Your car
  • Your backpack or purse
  • Your pockets

Police almost always need a search warrant in which a judge agrees probable cause exists prior to the search of a residence.

Vehicles, on the other hand are frequently searched by a police officer making a probable cause determination on the fly in the field without a warrant. Courts routinely allow these types of vehicle searches if the police had probable cause they would find evidence of a crime in the vehicle.

This is why police may have a drug dog sniff around the outside of a vehicle — if the dog alerts, the police have probable cause to search the car for drugs. 

If the police didn’t have probable cause to search your person, car, or residence, a criminal defense lawyer may be able to have evidence suppressed so it can’t be used against you.

Exceptions to Probable Cause Requirements

Exceptions to Probable Cause RequirementsThere are several important exceptions that eliminate the probable cause requirement to search that you need to be aware of. If none of these exceptions apply, police will need probable cause and possibly a search warrant before they can conduct a lawful search.

However, the police are experts at finding a loophole to search warrant requirements and finding evidence.

In fact, a high percentage of searches that seize incriminating evidence are performed without a search warrant because of one of these exceptions:


The most common way the police perform searches is through consent. At a traffic stop, police will often ask, “mind if I search your vehicle really quick to get you on your way?” If you say yes, you have consented to a search! 

Police also frequently say, “would you mind turning out your pockets for me really quick?” If you turn out your pockets, you consented to a search that the police probably didn’t even have probable cause to get a warrant to perform! It is so important to never consent to a search and request a lawyer instead.

Searching In Plain Sight

Police also frequently find evidence without a warrant through the “plain view doctrine.” This allows them to seize evidence that they can see from a place they are lawfully allowed to be. 

Sometimes police may fly drones in public airspace to see evidence in your yard. They may also see drug paraphernalia through your car window while standing on a public street. Neither of these “searches” require probable cause or a warrant, and in both cases police can use the evidence they find against you.

Exigent Circumstances

Exigent circumstances, such as a medical emergency inside a house, or a hot pursuit of a suspect inside a home, can also get police into a private area without a search warrant. Once lawfully inside, they can’t perform a full search, but they are allowed to seize evidence in plain view.

Search Incident to Lawful Arrest

Under the law, when police make a lawful arrest supported by probable cause, they are allowed to search the area surrounding the suspect. 

The area they are allowed to search is known as the area within “lunging distance” that courts believe must be searched for officer safety. This could include looking around the inside of a vehicle, a backpack, or the room in which they arrested someone, for instance. This could lead to discovery of a great deal of other evidence.

If your property was searched by law enforcement with or without a search warrant and you were charged with a crime, consult with experienced and aggressive Phoenix criminal defense attorneys to understand your legal rights. Many lawyers will offer a free initial consultation so that you can see if they are right for you.

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