I thought this was pretty good. Nothing amazing - as others have pointed out, protagonist haunted by the outcome of his callous deed is a fairly well-worn horror plot but it's lasted that long for a reason. In this case, it's not about originality but execution. And I liked the whole "CASEY CRIME-PHOTOGRAPHER thrown into a Kitty Genovese situation" framing.
Of course, these kinds of stories are ultimately reassuring, as they promise a universe that cares about "justice" - unless he's just lost his mind. Someone once posited that the EC TALES FROM THE CRYPT Story Model A (killer gets his comeuppance in poetically appropriate way, usually involving the risen dead) was a last gasp of Romanticism in an unlikely form - gosh darn it, the universe still cares about un-righted wrongs but the only vehicle it has left, that an audience will accept, is a rotting corpse and eye-for-eye violence.
Thanks for listening.
“Humor is a developed sense, stemming basically from cruelty. The more primitive a mind, the less selectivity exists. … A man slips on a banana peel and breaks his back. The adult stops laughing at that point, the child does not. And a civilized ego finds embarrassment as acutely distressing as physical pain. A baby, a child, a moron is incapable of practicing empathy. He cannot identify himself with another individual. He is regrettably autistic; his own rules are arbitrary…”
Lewis Padgett, “When The Bough Breaks” (1944)