The requirement for police to have probable cause to arrest someone, seize property or conduct a search comes from the Fourth Amendment of the U.S. Constitution. In order for a court to be able to issue an arrest warrant or a warrant for the search and seizure of property, there has to be probable cause.

Probable Cause and Warrants

When an officer seeks to get a warrant, he or she must sign an affidavit that the facts listed are true and provide probable cause to make an arrest, or search for and seize property. The judge that signs the warrant must only do so if he or she believes that probable cause does exist.

There are some circumstances in which a warrant is not needed to arrest someone or search for property. If a police officer witnesses a felony being committed in public, he or she does not need a warrant to make an arrest. Should such a warrantless arrest occur, the officer must still show that there was probable cause in order for the prosecution of the defendant.

Reasonable Suspicion

Probable cause has to come from specific facts –- not from an officer’s suspicion or hunch. Reasonable suspicion is all that is needed for a detention. Examples of detention include car stops or pedestrian stops.

For an officer to have reasonable suspicion, there must be specific facts that cause a reasonable person to think that criminal activity was at hand. More investigation is required to move from reasonable suspicion to probable cause. If someone is charged without probable cause or is arrested without probable cause, he or she can file a civil lawsuit for malicious prosecution or false arrest.

Probable Cause for Property Search and Seizure

Probable cause is often needed for an officer to search and seize property. If there is a search warrant, it must specify what items the officer is looking for and the location that will be searched. There are some cases when a search warrant is not needed. For example, if a situation threatens public safety or that evidence will be lost, a search warrant is not needed. A warrant is not needed if there are illegal items within plain site as long as the officer has a legal right to be present.

Questions About Probable Cause?

If you have been arrested and you don’t believe