What a wonderful idea!
Here's my contribution:

He said the headstones glowed at night, then he smiled provocatively. He had said a lot, had slurred and sputtered oaths to the gods of war, but he also said that the headstones glowed. He broke through the intoxicating effect of the potato juice, stopped reeling about the table for an instant, long enough to untwist his tongue, which up until that moment had been incapable of a dialect other than drunkenese, and told her point blank that the stones shimmered in the graveyard after the sun went down. Then, when he was sure that he had her attention, the officer grinned. Not the grin of affirmation that told her she was one of them, she was a comrade because she could take the joke without flinching, but the slow-forming sadistic half-grin of a dog-crazy wild man who’s spent too many nights on the tail-end of the sandman’s watch. His thin parched lips stretched and cracked, and then as if his face were rubber the center of his lips parted, seemingly punched through by a needle so a crescent could slowly rip to the corners of his mouth.
J.B.

OK, here goes:

Murder in the Dark

It was dark where he sat, watching. The only light in the room drifted down to his face so that, had anyone been able to observe him, they would have seen him outlined by it, limned in a ghostly halo of fuzzy light. But he had intruded on the scene in front of him, and he sat enraptured, hardly moving as he watched the lovers caress one another. He could even hear their endearing whispers. The door to the room swung open and the boy saw another person in the doorway. He could see that it was a woman even though her face was in shadow, the light from the hallway at her back, a dark figure no more defined than black silk. She saw the same scene that he was witnessing, yet from a different vantage point, and the woman was at first as still and quiet as himself. Then, she moved out of the light, determination in her step, until the boy could no longer see her in the unlit room. The music that had been playing changed suddenly from a romantic ballad to a tune of expectancy, or perhaps it was his imagination. The boy's pulse beat faster. He felt like a voyeur, but he could not bear to look away.
A struggling "oooof", then the sound of someone falling. The music had died. The sound of heavy breathing, and perhaps a flicker of movement to the right? What could be happening? His bladder was nearly full to bursting and he longed to get up out of this cramped sitting position and relieve himself. Yet he could not look away from what he strained to see. Something terrible was happening, he knew it, could sense it. He felt he could not bear the suspense. He had to know what was going on in front of him, no matter the cost, no matter if he wet himself, no matter if he was seen.
So he sat very still and listened until he heard the scream he knew was coming. It was then that he saw the shadowy figure slip out of the room, turning only once to look back at what she had done. Still, her features were not discernable. Who was she?
The boy remained in the dark, watching the murderess slip out the door. But what could he do? He didn't even know who she was...
And then his bladder could wait no longer. He arose from his seated position, standing carefully to relieve the cramps in his legs.
The music rose to a deafening roar again, startling him. People started yelling,"Sit down! You're in our way! We can't see!" and the boy moved to his left, and up the aisle of the movie theatre, urine dripping down his leg. He should not have waited so long, he knew it. His mother would surely punish him when he got home. But he couldn't help it: murder mysteries had always captivated his attention. Maybe he would even be a movie producer one day himself. Who could tell?