Anti Forensics Research Papers - Academia.edu (original) (raw)

On April 4, 2017 a Syrian government air-attack at Khan Sheikhoun, Syria was followed by reports, photographs, and video data that indicated a significant number of casualties from exposure to toxic gases associated with the attack. This event was immediately followed by allegations that the deaths and injuries were caused by nerve agent released from a small crater produced by an air-dropped bomb on an asphalt covered road. The crater's size, shape, depth, contained debris, and surroundings were extensively documented in numerous videos and photographs, but until now, there has been no clear, science-based explanation of how the crater was formed. In this paper, we have applied advanced techniques from computational mathematics and mechanics to perform a forensic reconstruction of the crime scene. Based on 3D image analysis, we first show that the alleged site of the chemical attack had been tampered with, and essentially all of the public reports about the scene around the crater depend on observations made after the tampering had occurred. Using mathematical modeling that utilizes the pertinent mechanics of fluids, solids, fracture and explosion based on LS-DYNA, our supercomputer simulation results have demonstrated the following: 1) We show that a bomb of cylindrical shape and high length-to-diameter (L/D) ratio that was attached to a metal tube arrived at a high speed and loft angle-in excess of 200 m/s and 45° respectively-and detonated at the surface of the asphalt road. The high L/D of the explosive charge and the attached metal tube indicates that the explosive charge was the warhead of a short-range rocket and the metal tube was the rocket's spent motor casing. 2) The cylindrical shape of the explosive charge, its loft angle, and its detonation at the asphalt surface completely explain the tear-shape (noncircular) of the crater rim and the location of deepest point in the crater-which is at the round forward edge the tear-shaped crater-perimeter (the crater is not deepest at its middle). Our calculations also reveal in detail how the empty rocket motor casing was carried forward by momentum after the crater was produced by the much faster action of the explosion of the warhead. The calculations show how the forward-moving casing then gets buried in the crater's forward wall and bent at a large angle by a violent torque, similar to that produced when a pole vaulter converts forward