In which situation can an officer enter without a warrant?

An officer can enter without a warrant in order to render emergency assistance because this circumstance falls under the exigent circumstances exception to the warrant requirement. When law enforcement believes that someone is in immediate danger or that evidence is at risk of destruction, they have the legal authority to enter a premises without first obtaining a warrant. This is justified by the necessity to protect life or prevent serious injury.

In contrast, conducting a routine check, inspecting property documents, and arresting a suspect generally require specific legal criteria to be met. Routine checks and inspections are not typically justified under exigent circumstances; they usually necessitate prior arrangements or warrants. When it comes to arresting a suspect, while there are situations (like hot pursuit or imminent destruction of evidence) where officers can enter without a warrant, it's more common for officers to obtain one beforehand unless exigent circumstances are also present.