What is a 'de facto arrest'?

A 'de facto arrest' refers to a situation where a law enforcement officer has effectively taken an individual into custody, even though the arrest may not have been executed according to the legal standards that govern proper arrests—most importantly, the requirement for probable cause. This term typically applies to circumstances where a person's freedom of movement is severely restricted, and they are subjected to an interrogation or detention without the legal backing of probable cause.

In this context, when an arrest is deemed 'unlawful' because it was made without the necessary probable cause, it forms the basis of what is defined as a de facto arrest. Such actions can lead to legal challenges against law enforcement, as these arrests can violate constitutional rights, particularly the Fourth Amendment’s protection against unreasonable searches and seizures. It's crucial to understand that while a de facto arrest may resemble a lawful arrest in practical terms, the lack of proper legal justification distinctly marks it as unlawful.

The other options describe legitimate scenarios involving arrests—such as those made with probable cause, valid consent, or at the scene of a crime—but these do not encapsulate the essence of what a de facto arrest entails. This nuanced understanding of unlawful detentions is important for grasping the broader implications of constitutional law in police practices.