how can a sister keep a life insurance policey

my mother passed away dec. 16 2010.I have 9 brothes and sisters . 8 of us not inculed in making her funeral arrangents,because of one sister, the4th one. We couldnt understand why she was doing this and the funeral home wuold not even talk to the rest of us they had to go throught her. we know why now. there was a insurance policey out on her .that she wanted to be splited between all of us .our sister wanted ous to sign a paper for her to be excuter and have it notaryized,but we did not . she will not give us the name of the insurance company either what can we do about this. we know this money was paid out of our mother bank account each mounth ,because she saw how much trouble she had when my fathr passed away in dec 2008 thank you