Custodial investigation is defined as

• A. The suspect's freedom of movement is restrained and they are questioned to elicit self-incriminating statements
• B. Any interview conducted by police
• C. An interrogation conducted without a warrant
• D. A simple questioning in a public place

Answer: (A)

Custodial investigation centers on the moment when a person is not free to leave and is being questioned with the aim of obtaining self-incriminating statements. The key factor is the loss of freedom plus interrogation to elicit admissions, which is why Miranda protections apply. If someone is simply interviewed while free to go or questioned in a public place without coercion, those are noncustodial encounters and do not carry the same safeguards.