Which step is crucial for PSOs to take when securing a crime scene?

Documenting observations is a crucial step for Protective Security Officers (PSOs) when securing a crime scene. This process involves accurately recording all relevant details such as the condition of the scene, any evidence present, and the actions of individuals in the area. The documentation serves multiple purposes: it provides law enforcement with a detailed account of what occurred, helps preserve the integrity of the scene, and can be essential for future investigations and court proceedings.

In a crime scene context, thorough documentation helps in establishing timelines and can be instrumental in capturing changes that may happen over time. Such information can also assist in identifying potential witnesses and helps ensure that no evidence is overlooked or altered. This step is pivotal in maintaining the evidentiary value of the scene until law enforcement arrives to take over.

On the other hand, the other options do not enhance the safety or integrity of the crime scene. Encouraging visitors to enter the scene may compromise evidence, leaving the scene unattended poses a risk of evidence tampering, and taking no action while waiting for law enforcement can lead to missed opportunities for collecting vital information. Therefore, documenting observations is the most responsible and effective action a PSO can take in this scenario.