I am happy that the sack & cupboad has moved as the light white is the shape of the cupboad with the sack on top, you see the top of the marks has a waved line over hanging the square marking show the sack & cupboad have been there for years?
so the sun over the years on the white wardrobe, with the cupboad against it and the sack on top had block the sunlight on the wardrobe leaving the outline!

But on the photo with big dot, you can see the wardrobe floor, you see 5 spend cases?

the cabinet could of been moved to find the cases and they all put in the wardrobe so the FSU don't lose them! or a patch of blood could been covered...
But I wonder way there a black spot on this photo... could there be blood on the bed leg.... showing Shelia's body had knock against the bed leaving blood stains?