I need help please

I asked this a few days ago but i still haven't found the answer.
I'm trying to look for a shoujo manga. I completely forgot the title and I haven't finished it yet, I forgot to put it in my reading list. The story, as far as I can remember, goes like this:

The girl's family was killed in a fire that was orchestrated by a man who seems to be a family friend. This guy is obsessed with her, I'm not sure but I think his obsession is one of the reason why he killed her family (i think it's the kind of reasoning , if she has nobody then she'll come to me kind of logic). I remember there was this other guy that is helping her

I'm sorry for the unclear plot, it has been a while since I read it. I suddenly remembered. Please help! I just can't get it out of my mind. Thank you