The entrance wound on the back of the president's head showed beveling on the inside surface of the skull indicating the direction of the bullet.
Sherri Fiester, Certified Senior Crime Scene Investigator and law enforcement instructor on beveling:
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Beveling
Bullets traveling through bone create marginal conical shaped fractures adjacent to the entry or exit site. The conical beveling characteristically appears as a symmetrical chipping out of bone forming an indentation surrounding the entry or exit point on the opposite side of impact. The small end of the cone touches the interior or exterior bone table from which the bullet entered. Tangential gunshot wounds to the head create elliptically shaped defects containing both internal and external beveling (Levy, 2012).
Some wounds present both internal and external beveling. Researchers attribute this pseudo-beveling in high velocity distance shots to the transference of kinetic energy to the skull as dislodged chips flaking off entry wound edges, producing the effect of beveling. Without careful examination, misinterpretation of an entrance wound as an exit wound is possible in all types of entries (Quatrehomme, 1998, Coe, 1981; Prahlow, 2010; Adams, 2010).
Based upon current forensic research, it appears
beveling cannot provide conclusive evidence of projectile direction. Incorrect assessment of direction can occur with tangential entries or exits, mistaken orientation, insufficient beveling, or the failure to recognize external beveling on entry wounds.
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