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What Is Probable Cause in CA?

  • Writer: Blair Goss
    Blair Goss
  • 10 minutes ago
  • 5 min read

Probable cause is one of the most important legal concepts in California law. It determines when a police officer can make an arrest, conduct warrantless searches, or take property without violating a person's constitutional rights.


At the core, probable cause protects citizens from unlawful police action. It ensures that every investigation, stop, or arrest is based on sufficient evidence and a reasonable belief that there is criminal activity associated with that action.


For those facing California criminal cases, understanding probable cause and the legal proceedings around it can make a difference when determining if an arrest is lawful or if a law firm needs to help fight an unlawful situation. They can answer questions like Can the police search me or my belongings without a warrant in CA?


The Definition of Probable Cause and Understanding Probable Cause in CA

The Definition of Probable Cause and Understanding Probable Cause in CA


Probable cause occurs when law enforcement has enough evidence and facts that would lead a reasonable person to believe that a crime has been committed, is being committed, or will be committed. This is not based on suspicious behavior or a "hunch."


In California, courts interpret probable cause as a "fair probability" based on the totality of the circumstances. This is not based on the belief or suspicion of law enforcement officers. Instead, it's based on the facts that support that.


All of this is based on the Fourth Amendment of the U.S. Constitution. It guards against unreasonable searches and seizures. California's state constitution shares this protection, too. It reinforces the need for probable cause before infringing on a person's rights.


When is Establishing Probable Cause Required?


Sufficient probable cause comes into play at several points during a criminal investigation. Every scenario requires a slightly different standard. This standard applies based on law enforcement actions.


1. Arrests

To make a lawful arrest — with or without a warrant — officers must have probable cause to believe the individual committed a specific crime. For example, if police witness someone breaking into a vehicle, sufficient evidence exists to provide probable cause for an arrest. However, if officers rely only on an unverified tip, the arrest could be challenged as unlawful as you can't base this on mere suspicion.


2. Searches

Probable cause is also required before police can search a person, vehicle, home, or personal belongings — unless an exception applies. Officers typically obtain a search warrant supported by an affidavit detailing the evidence that establishes probable cause unless exigent circumstances exist. Without sufficient justification, any evidence found during an unlawful search may be excluded under California’s “exclusionary rule.”


3. Seizures

If law enforcement wants to confiscate property as evidence, they must have probable cause showing that the property is connected to a crime. This applies to items such as drugs, weapons, or stolen property.


How Probable Cause Differs From Reasonable Suspicion in Criminal Defense


Probable cause is often confused with reasonable suspicion, but the two standards are distinct.


  • Reasonable suspicion is a lower threshold — it allows an officer to temporarily detain or stop a person for investigation (such as a traffic stop or pedestrian stop). An officer can investigate and do things like consent searches if they have a reasonable basis to do so.

  • Probable cause, on the other hand, is needed for more intrusive actions like arrests or searches. In this case, as long as it's lawful, evidence collected can be used in court.


In California, reasonable suspicion might justify a quick pat-down or brief questioning, but it cannot support a full search of a vehicle or home without additional evidence because there is no reliable information to prove probable cause.


Examples of Probable Cause in California

To understand how probable cause works in practice, you can look at these examples:


  • Example 1: An officer smells alcohol and observes slurred speech during a traffic stop following a traffic violation. These observations provide probable cause to administer a breath test and possibly arrest the driver for DUI.

  • Example 2: Police receive a tip about illegal drug activity. If they corroborate the information with surveillance or witness statements, that may establish probable cause to obtain a warrant, and the officer's warrant application will state this.

  • Example 3: Officers hear gunshots from a residence and see someone fleeing the scene. Those circumstances justify entry without a warrant due to probable cause and exigent circumstances. The officer's presence is the only thing that matters, as they do not need to approach a judge and get a warrant to arrest a suspect in this case.


Each situation depends on context — the same action may or may not be justified depending on the facts known to officers at the time. This is why it's important for a defendant to have these criminal defense attorneys in Sacramento CA at their side every step of the way, from the preliminary hearing to the full trial and appeal, if necessary.


Probable Cause and Search Warrants


In most cases, California law requires police to obtain a warrant before conducting a search. A warrant must be issued by a neutral magistrate based on an affidavit establishing probable cause. The affidavit should detail:


  • What evidence the officer wants to obtain

  • Where the evidence could be found in the area of the search

  • Facts linking the search to the location or person to criminal activity


If the information given to support eh warrant is weak or based on unreliable sources, a defense attorney can challenge the warrant in court. They can also consult on questions like Is "stop and frisk" legal in CA?


Exceptions to the Warrant Requirement

Though police officers will often do their best to get a warrant, there are exceptions. These include:


  • Exigent circumstances: This is like an emergency search - it prevents things like evidence destruction or the possibility to suppress evidence, the chance to escape, or harm another.

  • Search incident to arrest: Officers may search a person who is arrests and the nearby area for weapons or evidence. If the officer pulls evidence in this area, it could be used as evidence.

  • Automobile exception: Vehicles can be searched if probable cause shows evidence of a crime inside following a traffic infraction.

  • Plain view doctrine: Evidence that an officer can see may be seized without a warrant.

  • Consent: If a person voluntarily allows a search, no warrant is required and the officer can do a search.


Even with these exceptions, police must still meet the standard of probable cause. If that standard is not met, any evidence obtained may be suppressed.


Work with a Defense Attorney - Goss Law

Work with a Defense Attorney - Goss Law


At Goss Law, the team understands how critical probable cause issues can be in criminal defense. Challenging probable cause is the goal whether the case involves a warrantless search, a questionable arrest, or a DUI investigation. The team carefully scrutinizes every step law enforcement took.


By identifying probable cause violations, Goss Law helps protect clients’ rights and strengthen their defense in court. The firm represents individuals across Sacramento and surrounding California counties, ensuring that no case proceeds on unconstitutional grounds.

Reach out today for a free consultation.

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