Janitor's revenge

If you go to Montpelier, North Dakota, you will find a small school. If you go into the school, and then proceed to the basement, you'll find yourself in a boiler room. Go into the boiler room, and you'll see blood spattered on the walls. On closer inspection, the blood forms a pattern... Words. Before you can read the blood, the lights turn off. You try to leave, but the door has slammed shut and is locked. It is said that fifty years ago, some punk kids locked the janitor in the boiler room while it was malfunctioning, exploded, and killed the janitor and the children. The spirit of the janitor now haunts the school, and lures children into the boiler room where he murders them in an act of revenge.