What is the first action to take when a detective relieves you during a preliminary investigation?

The first action to take when a detective relieves you during a preliminary investigation is to brief the detective. This step is crucial because the detective needs to be fully informed about the situation and the initial findings or actions taken. Providing a thorough briefing ensures that the detective can assess the situation accurately and make informed decisions moving forward.

In the context of an investigation, communication is key. The detective relies on the information gathered by the uniformed officer or investigator first on the scene. This briefing typically includes details such as the scene's status, any witnesses encountered, relevant observations, and evidence collected. By doing this, the detective can effectively continue the investigation without missing critical details.

Taking this step fosters cooperation and ensures continuity in the investigation process. Other options, such as contacting the detective's supervisor, collecting evidence, or leaving the scene, do not promote effective collaboration and may hinder the investigation. Therefore, briefing the detective is essential in facilitating a smooth transition and maintaining the integrity of the investigative process.