What key aspect does "interrogation" leverage in a criminal investigation?

Interrogation in a criminal investigation primarily involves questioning suspects to elicit information that can provide insights into the crime or the suspect's involvement. This process is crucial as it allows investigators to clarify details, gather admissions or confessions, and understand the suspect's narrative regarding the events in question.

By engaging with suspects through structured questioning, investigators can obtain valuable leads or corroborate evidence already gathered. This method is integral to understanding motives, relationships, and potential witnesses or accomplices, thereby providing a comprehensive picture of the criminal case at hand.

Other options like surveillance or gathering forensic evidence serve different roles in the investigative process, but interrogation specifically focuses on direct interaction with suspects to extract information that is often not available through physical evidence or reports.