What is necessary for an arrest based on probable cause?

For an arrest based on probable cause, the correct choice centers around having a belief that a crime was committed. Probable cause means that there is a reasonable belief, based on facts, that a crime has been committed and that the individual in question is connected to that crime. This belief must be founded on adequate evidence or circumstances that would lead a reasonable person to conclude that a suspect has engaged in criminal activity.

While reasonable suspicion involves believing that a crime may be occurring or about to occur, it does not meet the threshold of probable cause, which requires more substantial evidence. Observing a crime in progress represents a strong form of probable cause, but the lack of direct observation does not negate the possibility of having justified belief based on other circumstances. Meanwhile, a warrant signed by a judge is not necessary for every arrest; probable cause alone can suffice in many situations. Thus, belief that a crime was committed encompasses the essence of probable cause necessary for an arrest.