How large should the inner perimeter be in relation to the actual crime scene?

The inner perimeter should be at least twice the size of the crime scene to effectively secure the area and allow for thorough investigation without contamination. This larger space provides a buffer zone that helps protect evidence from external disturbances and ensures that investigators and officers can work without interference from the general public or other parties who might inadvertently enter the scene.

By having a perimeter that is significantly larger, it facilitates the management of potential witnesses, suspects, and other individuals who may be present, allowing law enforcement to control the situation better while preserving the integrity of the crime scene. Additionally, a larger perimeter can accommodate the needs of various investigative teams and support staff who may require access for processing evidence and conducting interviews.