Who is typically the person requesting an investigation, often being a victim of a crime?

The person who is typically requesting an investigation and often is a victim of a crime is known as the complainant. This individual usually presents information about the incident or crime they have experienced or witnessed, which initiates the investigation process. The complainant plays a crucial role in providing law enforcement with the details and context necessary to start investigating.

In contrast, a witness may provide information about an incident they observed but does not necessarily have a personal stake in the matter. The accused refers to someone who is being charged with a crime, while the defendant is a broader legal term used to describe someone who is defending against a charge in court. Neither of these terms indicates a party that would request an investigation. Therefore, identify the complainant as the key figure who engages law enforcement to take action regarding a crime they have suffered.