Which technique involves interactions with individuals to gather information in investigations?

The technique that involves interactions with individuals to gather information in investigations is interrogation. Interrogation is a specific process wherein law enforcement personnel engage with a suspect or witness to obtain details, clarify facts, and extract relevant information that aids in solving a case or understanding a situation better. This technique is crucial as it can lead to confessions, admissions, or other valuable insights that might not be available through physical evidence alone.

In interrogation, the approach often includes establishing rapport, asking open-ended questions, and employing various strategies to encourage cooperation and truthfulness from the individual being questioned. This interaction is a skilled aspect of an investigator's role, emphasizing communication and psychological tactics to elicit information.

Other options like surveillance focus on observing subjects without direct interaction, community policing emphasizes building relationships within the community to enhance public safety and trust, and traffic enforcement pertains to ensuring adherence to traffic laws, none of which inherently involve direct questioning or gathering information in the investigative context.