Also known as: probabilem causam · probable cause
Written by attorneys · grounded in primary & secondary sources — see below
A reasonable basis for belief that a particular fact is true or that a legal standard has been satisfied. The standard requires an objectively sufficient showing that supports the belief without demanding certainty or proof beyond a reasonable doubt.
Federal agents received an affidavit describing drug activity at Paula Pierce's home. The magistrate reviewed the facts and concluded that a fair probability existed that contraband would be found. The warrant issued and the subsequent search proceeded under the Fourth Amendment standard.
Officers arrested Patrick Phan without a warrant after observing him sell narcotics. Prosecutors filed a complaint the next day that recited the observed facts and the officer's training. The magistrate determined the complaint satisfied the probable-cause requirement for continued detention.
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Priya Prasad challenged her aunt's will on undue-influence grounds after discovering medical records showing the testator was medicated at signing. The personal representative invoked the no-contest clause. The court found that the medical evidence supplied probable cause for the contest and refused to enforce the forfeiture.
An informant told police that Portia Price kept stolen electronics in her garage. Officers corroborated the tip with surveillance and the informant's prior accurate reports. The totality of circumstances established a fair probability that evidence of crime would be found, so the warrant issued.
Peter Park filed a petition alleging his father's will was forged after obtaining handwriting samples from the decedent's bank records. The executor sought to enforce the penalty clause. The court held that the samples supplied probable cause for the proceeding and declined to apply the forfeiture.
A detective presented Pierre Poulin's file to the prosecutor after an arrest for embezzlement. The only evidence consisted of uncorroborated coworker statements contradicted by bank records. The prosecutor declined to file charges because the evidence did not establish probable cause.
Probable cause requires a fair probability that evidence of a crime will be found or that the defendant committed the offense. Reasonable suspicion is a lower threshold that justifies only a brief investigative stop or frisk.
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An informant's tip is evaluated under the totality of the circumstances. Veracity, reliability, and basis of knowledge remain relevant, but a strong showing on one factor can compensate for weakness on others when the overall facts show a fair probability of criminal activity.
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A no-contest clause is unenforceable if the contestant had probable cause to institute the proceeding. Courts apply an objective standard: whether a reasonable person would believe the challenge had merit based on the information available at filing.
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A prosecutor must refrain from prosecuting a charge known to lack probable cause. Filing charges without that foundation violates professional-conduct rules and exposes the prosecutor to ethical discipline.
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No. Probable cause is judged by the facts known when the proceeding began. Subsequent dismissal does not retroactively eliminate the objective basis that existed at the outset.
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…of police officers in investigating crime. See Escobedo v. Illinois , 378 U. S. 478, 492. When an individual is in custody on probable cause, the police may, of course, seek out evidence in the field to be used at trial against him. Such investigation may include inquiry of persons not under restraint. General on-the-scene…