Fascinating. Wouldn't contra-coup indicate a blow with a stationary object? Just thinking about the physics of it, I would think that a moving object would not cause the brain to recoil against the opposite side of the skull...
There are too many nuances to it and exceptions to the rule for me to comment on it from just this.
It was a topic we debated for many years and I'm still not clear on what actually happened.
I'd say a brick is a good possibility as the item used for the blow. It's size and shape allows for the good control and tremendous force exhibited in the wound.