How do I tell my friend (girl) that I like her sister?

[Uncle C]

My friend is a friend on Facebook. We used to hang out when she dated my best friend many years ago. My best friend and I have since gone our separate ways. She and I still talk a little here and there on Facebook. I've started to take a liking to her sister and I don't know how/what to say. I mean, her sister (the one I like) does not even know me.

To add a side twist to the story, I used to work with their father. No issues with him and I would say that he feels the same way. Him and I talked almost every day and had a lot of good conversations. So the girl that I like doesn't know me, but I know her sister (my friend) and her father (previous coworker).

Any ideas?

[postal p]

She might try to sabotage you. It is a delicate situation.