My Father Died and No One Told Me?

My dad's family is a bunch of spiteful jerks. I live 600 miles away from him and it's been hard to have a relationship with him with them down his back all the time and not giving him my messages when I called. We've never stayed in touch that much because of them since I was 12. They were mad I wanted to live with my mom so my dad actually had to sneak around just to see his 12 year old daughter. It was pathetic on his behalf to not stick up for himself and me but he was still my father. I got a message on my facebook from a long time family friend telling me to call her and she tells me he passed away 6 weeks ago and they didn't even tell them, one of his best friends. They told no one who would possibly tell me. They didn't even put an obituary out in case I found out. They are deeply disturbed people, obviously, but now it makes me question if they're trying to hide something from me that either he didn't put in a will or that he actually willed to me. His sister had control of everything so since I was 12 I knew I wouldn't be willed anything but now I'm curious. What can I do? I mean, who the hell doesn't tell a man's only daughter that he's passed away? Then to go so far to hide it that I spent 6hrs peicing together information that finally leads me to believe he passed around March 20th of 2012. I'm too mad to grieve properly and I want to make sure that their plan doesn't follow through because if my dad left me something then he wanted ME to have it and I would like to have something of my dad besides a picture when I last was able to visit him.