Here is another storyline that I've thought of:
Inside a bathroom, we see a normal boy sitting on the toilet, after he flushes, the camera switches to the bathtub where we see a dead body lying there with blood. Then the boy goes to wash his hands, but puts his looks down onto the sink, the camera goes close up on the door lock, showing that the door wasn't locked. After the boy washes his hands, the camera slowly goes down facing the bathroom floor, seeing blood everywhere, splattered on the floor with some flesh.
The next setting is the garden, we see the boy sitting on the swings, reading a book, then he goes inside the shed to fetch some fish food to feed the fish, after that, we see tools with blood on them. There will be mysterious music added to this short movie.
The final part, when the boy goes to bed, the opposite bed next to him, we see another dead body.
This might not be in the final cut, but it is just an idea. If we do stick to it, we will change it a bit.