The Explosive Ordnance Office at Aerospace works with the Law Enforcement and Corrections Technology Center, collocated at Aerospace, to help solve crimes with the Los Angeles Police Department. In two instances, expertise in explosives behavior and the analytical and laboratory capabilities at Aerospace contributed to solving bomb-related cases.
In the first, an explosion occurred in a Los Angeles apartment that seemed to be caused by fireworks. But detectives wanted to find out if the occupant had actually been making high-explosive materials in the apartment. Based on analysis of the crime scene, and using empirical calculations to relate blast-wave characteristics to damage caused by the explosion, Aerospace was able to prove that high explosives had been present at the time of the accident. The amount of structural damage was not consistent with the burning of fireworks, and the blast overpressure corresponded to the output expected from the amount and type of explosive materials inferred by the police. The case eventually went to trial, and the suspect was convicted of felony possession of high explosives.
In another case, Aerospace analyzed evidence collected after a blast in a residential area. The case involved an improvised explosive device placed in the front axle of a pickup truck. An empirical fragment-acceleration model known as the Gurney Acceleration Method was used to analyze the final velocity of the fragments to determine the explosive energy necessary to yield the observed fragmentation pattern. The findings were consistent with the properties of two types of explosive materials, evidence of which were both found at the suspect's home, and either of which could have been used in the bomb. Both types of explosives were consistent in energy output with the fragment distribution. The only significant chemical marker to distinguish the two explosives was the fact that one molecule contained nitrogen and the other did not. Additional investigations of the scene produced small, spherical metal particles that were thought to come from either the bomb casing or the sheet metal of the truck. These particles were thought to be solid droplets until they were examined by Aerospace and found to be hollow bubbles. Suspecting that these bubbles might have trapped gases from the explosion, analysts examined them using a mass spectrometer. The distribution of elements inside them confirmed that the explosive containing nitrogen had been used. This information was then used to convict the suspect.