Police officers and detectives on the scene of an explosion must first gather evidence in order to better understand what they are dealing with, as well as for future prosecutions.
As occurred during the aftermath of the 1993 World Trade Center bombing in New York, the actual search of the scene of an explosion is possibly the most important aspect of the investigation. Investigators should start with a quick visual search in order to familiarize themselves with the area.
They should keep in mind that there could be multiple bombs planted in the immediate area of the blast and these additional bombs are planted for one purpose and one purpose only: to kill or maim the emergency personnel who respond to the initial blast. If a suspicious object is sighted during this phase of the crime scene search, detectives and other emergency personnel will evacuate the scene until bomb technicians can determine the nature of the threat or disarm the additional devices.
Once the visual search is completed, with the utmost care and continuous caution, detectives and police officers will start removing large pieces of debris from the area of the explosion. They should keep in mind that there could be live electrical wires or ruptured gas lines in the immediate work area. The scene of an explosion should be viewed as hazardous at all times.
When any of the large pieces of debris are removed, they are stored within a protected location, catalogued as to the description and place of recovery, name of the officer involved, and held at the location for a subsequent detailed search. After the large pieces are moved and secured, detectives and officers must get on their hands and knees and start searching the debris looking for anything that appears foreign to the scene such as: leg wire (color-coded wire used in blasting caps); parts of a blasting cap; remains of a safety fuse; battery fragments; metal pipe fragments; other metal fragments (clock, propane tank, etc.); and bomb container fragments (metal, leather, canvas, cloth, paper, etc.).
Whenever anything considered significant is found, it will be bagged and marked for identification purposes. The location, time, date, name of officer or detective, shield (badge) number and command should always be marked on evidence bags.
If there are other data, these should be written on a separate report form or piece of paper and enclosed in the evidence bag. Investigators will never mark or deface the recovered evidence.
Detectives and officers at a blast scene must be persistent and they may have to go over the same area numerous times before uncovering anything of value.
Ultimately, they will have to conduct a sifting operation because some objects such as watch springs and other internal mechanisms are so small that they could easily be overlooked by investigators. The type of search to be conducted at the scene of an explosion will be determined by Bomb-Section personnel and investigators will be guided by their decisions. A properly conducted search may yield fingerprints,
serial numbers, manufacturers’ names, price tags and many other investigative aids which would eventually help in solving the crime.