I didn't think I could feel more sorry for Becky after she was murdered..... but it sounds like she had a pretty horrible life, not belonging anywhere, being resented by some members of the family, fearing her step brother and so on. I know we don't know what is true from what we are hearing, but there must be elements of truth in a lot of it.
Even her home doesn't look very nice, and her bedroom with its broken furniture and blinds makes me sad. I don't have a daughter, but even with my sons, always tidy up their rooms and make them look nice for when they come home from school and college, and always buys things to make their rooms comfy and personal - like nice rugs, cushions and so on. Her room just look so bleak. I don't meant she didn't have money spent on her - it just doesn't look like a room a teenage girl could be comfy in, if you get what I mean. It looks like its been neglected for a long time.