From the post mortem
His body condition was good.
His tongue was blue (cyanotic) as a result of oxygen deficiency. It was also bleeding because the dog had bitten through it.
External examination of the skin showed no obvious signs of trauma except one cut on the upper side of his neck.
When removing the skin multiple signs of trauma could be seen. There were multiple areas of subdermal (under the skin) bleeding and bruising. This is a result of direct trauma inflicted to the body. (Similar to a human bruise.) The area around the neck was affected severely and the colour of this area differed from the rest of the body in the sense that it was much redder and bloodier. This is a result of bruising to the tissues in this area.
The rest of the body was pale pink (normal) except for the local areas of bruising, as mentioned earlier. Around the neck it was very bloody and red. The trachea itself had bruises on its outside indicative of direct trauma. The thorax revealed partially collapsed lung tissue. This could be as a result of post mortal changes, but considering the time frame it is more likely to be as a result of suffocation.