What should an officer observe to make a lawful arrest without a warrant?

For an officer to make a lawful arrest without a warrant, they must observe an offense being committed in their presence or a serious crime. This is rooted in the principle that for a warrantless arrest to be justified, it must be based on immediate and observable facts, enabling the officer to act in real-time to prevent further crime or harm.

In situations where an officer witnesses an offense directly, they are better positioned to assess the circumstances and determine the necessity for arrest. This direct observation ensures that the officer has concrete evidence to support the necessity of the arrest and protects against potential legal challenges regarding the validity of the arrest.

While proof of prior criminal activity may indeed raise concerns or add to an officer’s understanding of an individual’s behavior, it does not itself provide grounds for a warrantless arrest. An offense committed out of the officer's view similarly does not allow for immediate action since the officer cannot ascertain the circumstances directly. General suspicious behavior alone lacks the substantial grounds necessary for arrest without a warrant, as it does not constitute a clear and present violation of the law.

Thus, the necessity for immediate action in response to a visible offense or serious crime is crucial for lawful warrantless arrests, making the correct choice pertinent and foundational to police practice in New South