A Guide for Investigating Bomb and Explosion Scenes: Evaluating the Scene

Note: At the time the scene is determined to involve a bombing or other crime, the investigator must address legal requirements for scene access, search and evidence seizure.

Once the principle investigators arrive on the scene, they must coordinate with the first responders and conduct a scene walkthrough. Primary investigators at a bombing and explosion site should follow these steps:

Define the investigator's role. The primary investigators should coordinate with the incident commander and first responders to determine what occurred and to assess the situation. Subsequent procedures will vary depending on the magnitude of the incident.

Prior to entering the scene, the investigator(s) should:

  • Identify and introduce himself or herself to the incident commander.
  • Interview the incident commander and first responders to evaluate the situation, assess safety concerns, and determine the level of investigative assistance needed.
  • Conduct a briefing with essential personnel (e.g., law enforcement, fire, EMS, hazardous materials and utility services personnel) to:

    Caution: Only bomb disposal personnel should handle any suspected devices that are located. Take no further action until the devices have been identified or rendered safe.

    • Evaluate initial scene safety to the extent possible prior to entry.
    • Make sure that a search for secondary explosive devices has been conducted.
    • Make sure that the scene is secure, that a perimeter and staging areas for the investigation have been established, and that all personnel work to prevent contamination of the scene.
    • Ensure that a chain of custody is initiated for previously collected evidence.
  • Assess legal considerations for scene access (e.g., exigent circumstances, consent, administrative/criminal search warrants).

Ensure scene integrity. The investigator(s) must establish security perimeters and staging areas, contamination control procedures, and evidence collection and control procedures.

Prior to evidence collection, the investigator(s) should:

  • Establish procedures to document personnel entering and exiting the scene.
  • Establish and document procedures to prevent scene contamination.
  • Establish and document procedures for evidence collection, control, and chain of custody.

Conduct the scene walkthrough. The investigator(s) must conduct a walkthrough to establish the scene's parameters and acquire an overview of the incident.

The investigator(s) should:

  • Reevaluate scene requirements (e.g., boundaries, personnel, equipment).
  • Establish an entry and exit path for personnel.
  • Identify safety concerns (e.g., structural damage, secondary explosion devices, unconsumed explosive materials, failed utilities, hazardous materials) and to the locations of physical evidence.
  • Ensure preservation and/or collection of transient evidence.
  • Attempt to locate the seat(s) of the explosion(s).

Secure required resources. After the walkthrough, the investigator(s) should meet with emergency responders and investigative personnel to determine what resources, equipment, and additional personnel may be needed.

In the meeting, the investigator(s) should:

  • Assess the nature and scope of the investigation based on information obtained during the walkthrough and from all available personnel.
  • Advise personnel of any secondary devices or other hazards found at the scene.
  • Make sure that one list of victims/potential witnesses is developed and that their accounts of the incident are documented.
  • Make sure that required evidence collection equipment and processing and storage facilities are available.
  • Secure required equipment as determined by the scene conditions, such as light and heavy equipment, handtools, specialty equipment, and personal safety items.
  • Ensure that sufficient utilities and support services have been requested (e.g., electricity, food, trash removal, sanitary services, other public services, security).
  • Give emergency responders and the investigation team their assignments for scene documentation and processing.
  • Remind personnel that evidence can take many forms; and should not be limited solely to components of the device(s).
Date Created: June 1, 2009