Final answer:
No, an officer does not need probable cause to perform a 'Terry' stop, but rather a reasonable suspicion of a crime.
Step-by-step explanation:
In order to perform a 'Terry' stop, an officer does not need probable cause, but rather a reasonable suspicion that the person has committed or is about to commit a crime.
According to the Supreme Court case Terry v. Ohio, police may stop and frisk a suspect for weapons if there is a reasonable suspicion that the suspect is armed and dangerous. This reasonable suspicion standard is lower than the requirement of probable cause.
Probable cause is generally required for arrest warrants, but there are exceptions for felony crimes where the police can arrest someone without a warrant. However, for a 'Terry' stop, probable cause is not necessary.