What is one key step in the process of securing a crime scene?

Establishing boundaries and preserving evidence is a crucial step in securing a crime scene because it helps maintain the integrity of the scene for investigation. This process involves defining the perimeter of the crime scene, which prevents unauthorized access and potential contamination of evidence. By doing so, investigators can ensure that all physical evidence, such as fingerprints, DNA, and other trace materials, remain undisturbed and in their original condition, which is vital for accurate analysis and prosecution.

Additionally, preserving evidence is essential for building a reliable and credible case. Any disturbance at the crime scene can lead to the loss or alteration of critical evidence, which may ultimately undermine the investigation's outcome. This step is foundational to the forensic process, as it lays the groundwork for subsequent evidence collection, documentation, and analysis.

The other options, while important in their own contexts, do not directly pertain to the immediate actions necessary for securing a crime scene. Conducting interviews with suspects occurs later in the investigation process; documenting expenses is an administrative task rather than a procedural one; and public announcements can risk compromising the investigation by revealing sensitive information.