Probable Cause

You’ve probably heard it on the tv shows – A cop has to have “probable cause” to arrest. But what is probable cause and why is it so important? The best definition of probable cause that I have heard is:

“There must be probable cause to believe the particular person committed or is committing a particular offense”

The probable cause test is an objective one. Subjective intent is irrelevant. So subjective good intent will not be a sound basis for probable cause nor will subjective bad intent be the basis to void probable cause.  Since the definition of probable cause is relatively vague each case must be evaluated on a case by case basis using a totality of circumstances test. Hearsay is allowed in a probable cause determination. However, the Court’s will look at where the hearsay came from. For example, was the hearsay from a criminal informant or a citizen? 

Often a stumbling block for first year law students or rookie cops is that probable cause is NOT needed to effectuate a stop or to detain a person. A cop only but need to have “reasonable suspicion” that a crime has or is about to occur to initiate a vehicle stop or to halt someone. 

Finally, why is probable cause so important in arrests? Both the United States and Tennessee Constitutions provide against unreasonable search and seizures. The Tennessee Constitution goes a bit further to state that “general warrants, whereby an officer may be commanded to search suspected places, without evidence of the fact committed, or to seize any person or person not named, whose offenses are not particularly described and supported by evidence, are dangerous to liberty and ought not to be granted”

So our very own constitution warns us against warrantless arrests that do not have the prerequisite probable cause in that such arrest powers are dangerous to our liberty.