Even if the neck hit had not severed the artery, the hydro-static shock wave likely ruptured many blood vessels in the victims cranium.
This death was probably from blood loss, but even without the blood loss, he would have likely died from cranial anyuerism.
Don't be too sure that the weapon found in the woods was the actual weapon used. It could easily be a plant designed to throw off investigators and/or a way to increase political division.
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