The Neighbour's House

My neighbour's house is normal. There are two stories, stairs, and a tiny porch. A red door, and many windows with pretty crimson shutters.
My neighbour's house is normal. The lights are on when they need to be, and off when they don't. The grass is mown, and there are sometimes cars in the driveway.
My neighbour's house is normal. Sometimes I can see into some of the rooms. Always when I'm not really trying. The rooms are nice, with a warm colour scheme and polished wooden furniture. There is one room that is entirely white. A bare bulb swings from the ceiling. From the outside, I can see no furniture. The walls are old and stained.. There are no shutters on that window.
My neighbour's house is normal. I see them sometimes. They're gone most of the day. We wave when we see each other, coming or going. Those two seem nice. Didn't they used to have a son about my age?
My neighbour's house is normal. They turn off their lights about the same time we do. Except in that one room. The lights in the white room stay on late each night. I tried to watch them, once, to see how late they stayed on. I fell asleep. When I woke up, they were already off.
My neighbour's house is normal. Sometimes I hear sounds from the house. Almost like muffled screams. Everyone gets night terrors, it's common knowledge that, at night, everything can sound scary.
My neighbour's house is normal.
Except when it isn't.