“Asphyxia causes visible indicators on the body”
Not actually true, especially in slow pressure stranglings vs. violent chokings or when there is a ligature.
It is arguable that the reduction of blood flow to the brain by pressure on one carotid plus reduced oxygenation of his blood from the knees in the back compressing his lungs reduced the o2 to his brain over the almost 10 minutes enough to stop his heart.
It’s the violent pressure that causes 100% stoppage of oxygen that results in visible indicators and a much quicker death.
I was referring to cyanotic discoloration, but not to signs left by any sort of traumatic strangulation, as described here-