It's the faces that haunt Jim. They're why he never sleeps in the dark, and why there's a loaded handgun beside his bed at all times. Normally he doesn't bother with them: just take the clients' payments and then hand over the tasks to the appropriate people. That's usually all he does.
There's only been a few times he's had to get his hands dirty, and he regrets all of them. There's one in particular that bothers him, though; one in particular that will never leave him alone.
She had evenly tan skin, but too dark for getting it in London. It was natural, though, which meant she had been abroad recently. Her wavy black hair fell to her shoulders. The side part and the way it was just starting to frizz only framed her angular face in a becoming way. The girl's looks did little to stop the 40 millimeter bullet that was the end of her, but they made sure James Moriarty never forgot her.
It was supposed to be a simple job: Locate the girl, locate the information, dispose of both. The first was done with relative ease, but once she was able to talk she refused to do so. No amount of threatening, blackmailing or torture would get the abducted girl to tell them what Jim needed to know.
The last thing Jim saw before he pulled the trigger were her eyes. They were ice blue and emotionless, silently staring and condemning their owner's murderer. It's the eyes, they eyes and the silence, that stay with Moriarty the most.
The walls in James Moriarty's room are covered in innumerable bullet holes from when he awoke screaming, trying to protect himself from those silent, condemning eyes. He'll go through phases of hysteric crying because they won't go away, and fits of rage because they're still there, taunting him.
Sherlock Holmes was his distraction from it all. The detective kept the criminal mastermind busy, and awake. Kept his mind off of those eyes, and the girl attached to them. It was nice, but Jim knew it couldn't last. And he was right.
Right before James Moriarty pulled the trigger, he scanned Sherlock's face. In it he found the same ice blue eyes. "How fitting," he thought, before ending his life. The blue eyes that had haunted his dreams while he was alive had been the cause of his death.