My sister demanded my mother turn over 18000.00 to her for safe keeping My sister in turn has spent the money and still tells my mother she is keeping her money safe Has she committed a crime?

Yes, this would be a crime. It is fraud. She has stolen money from your mother and spent it. She has also lied to your mom, she told her she was keeping it for safe keeping. Could have, but to me sounds like it was because someone threatened her life or something like that. i dont think so, but i do think she should tell her mother what she has done because one day her mother might ask her for it because she needs it and if she tells her then,then they could get in some very bad trouble