Under what condition can police arrest someone without a warrant?

The correct understanding of when police can arrest someone without a warrant hinges on the concept of "probable cause." Probable cause exists when the police officer has enough facts and evidence to reasonably believe that an individual has committed a crime or is committing one at that time.

While reasonable suspicion allows police to stop and briefly detain a person to investigate further, it is not sufficient for an arrest. Arrests require a higher standard, and therefore, an arrest based only on reasonable suspicion would not stand up in court.

In situations where a police officer witnesses a crime being committed, they have clear probable cause to make an arrest on the spot. Similarly, public safety concerns may lead to an arrest, but again, the legal framework typically supports the need for a demonstration of probable cause rather than mere suspicion or concerns.

Thus, the ability of police to make a warrantless arrest is fundamentally tied to having probable cause, underlining the importance of this standard within law enforcement practices.