He's the guy.
His wrist and the back of his hand are scraped up as well.
It's his left hand and he is left-handed.
Hypothesis:
BO- Hey Mike, I'm tired of your stinky hole and you're tired of my stinky hole, let's go screw Chef!
MO- I hate America and white people. Yay let's go screw Chef!
CHEF- All Hell No!!
And you know the rest of the story.
THE END