The Basics of Probable Cause

December 24, 2025

People in America have certain inalienable rights, and police and other authorities must respect those rights anytime they interact with the public. But if that’s the case, why does it seem like police and federal authorities are increasingly investigating, detaining, and even arresting people without valid justification? In many instances, local communities have alleged that police and federal agents are acting without probable cause.

The LLF Law Firm Criminal Defense Team believes everyone deserves to feel free, safe, and secure in their local community. We defend Pennsylvanians facing criminal allegations and challenge unlawful stops, searches, detentions, and arrests that lack probable cause. Call the LLF Law Firm today at 888-535-3686 or contact us online to get started.

What Is Probable Cause?

In a perfect world, police cannot arrest someone, get a warrant, or conduct a search without probable cause. Probable cause is a belief based on specific facts that a crime has been, is being, or will be committed. Examples include direct observations, like contraband in plain view, and reliable reports from witnesses or victims. If the known facts wouldn’t lead an ordinary person to think a crime likely happened, there is no probable cause.

What this means in practice is that police cannot arrest or detain you without good reason. If officers want to obtain an arrest warrant, they must present sworn affidavits that lay out those facts to a judge. And if officers want to arrest you without a warrant, they must still have those facts at the moment they act, not post hoc explanations. The same general standard applies to searches, protecting you from unlawful searches.

Even after an arrest, Pennsylvania must clear an early checkpoint at the preliminary hearing and show probable causethat a crime was committed and that you likely committed it. The bar is low, but it is present. If prosecutors cannot meet it, the LLF Law Firm can help dismiss those charges.

When Authorities Don’t Respect Probable Cause

Across the country, communities have raised alarms about detentions and arrests that appear to lack valid justification—particularly in immigration enforcement. Remember that constitutional limits apply to all government actors, not just local police, and the protections of the Constitution extend to all people in the US.

In Chicago, advocates have alleged that federal immigration agents violated a consent decree by detaining 22 people, including a US citizen, without a lawful basis. In Colorado, civil rights groups have filed a lawsuit alleging that ICE has made warrantless arrests without individualized probable-cause findings. More and more people are coming into contact with federal agents, and more and more allegations of unlawful detentions by federal agents are arriving every day.

Pennsylvanians deserve to feel safe in their communities. If officers stop, detain, or search you, your home, car, or phone, they need facts to support their actions. When they cannot point to those facts, a court can suppress the evidence or dismiss the charges against you. Make it known that you do not consent to unlawful searches and exercise your right to legal representation by immediately contacting the LLF Law Firm. Our Criminal Defense Team will get to work reviewing the officers’ actions to determine whether they violate your rights.

Protect Your Rights With the LLF Law Firm

Probable cause protects people from baseless arrests and invasive searches, and no police officer or federal agent can take that right away from you. If you believe your rights were violated, the LLF Law Firm is here to help.

Our Criminal Defense Team will review all aspects of the incident, including the initial detention, the reasoning behind it, and the affidavits supporting it. Call the LLF Law Firm today at 888-535-3686 or contact us online to get started.