Probable Cause or Reasonable Suspicion

What’s the difference?

A driver is steering his Chevy Camaro down the highway within the speed limit late on a Saturday night. Can a police officer pull him over to make sure he is not drunk? Can a suspicious-looking person peering into car windows while holding a long screwdriver be arrested for attempted burglary? The answers to these questions can be quite complicated.

Probable cause

Generally speaking, a police officer must have probable cause before arresting a person. Probable cause means there is good reason to believe that the suspect has committed or is planning to commit a crime. That means there is a fair probability that the suspect has engaged or will engage in such a crime. In a recent case, the Superior Court ruled that the police had probable cause to stop a suspected drug dealer and obtain a court order to place a GPS device on his vehicle because they had information from a number of informants.

Reasonable suspicion

On the other hand, an officer only needs a reasonable suspicion of a crime to detain a suspect for a brief period of time. The officer can only detain the suspect, however, if the subsequent detention can confirm or disprove the officer’s suspicions. Thus, the police can’t stop a random driver on the highway if they merely suspect that the motorist had previously been speeding unless they have specific facts that lead them to such a belief. Police can stop a driver if they suspect the driver is drunk since the subsequent investigation determines whether indeed the driver is intoxicated.

Note that the Commonwealth allows police to set up a checkpoint where they stop all drivers meeting certain pre-determined criteria as part of a systematic program like checking for license and registration or DUI. There is no reasonable suspicion or probable cause required for checkpoints.

Many criminal convictions are challenged on the grounds that the police did not have probable cause or even a reasonable suspicion for the defendant’s arrest. If you have been charged with a drug crime, felony or misdemeanor, contact a criminal defense attorney experienced with these types of challenges to help you win your case.