Need some Help

[lotakidz8]

about 5 months ago my sister had a little safe at my dads house and told my dad that she had 64000 in this safe and someone stole it... my dad told her to call the police but she didnt at first then 3 days after that she called the police... the police came and got the safe and she told them that there was only 20000 in it.... the cop said that there where no signs that anyone had broken in it.... the cop took the safe and then told me my husband and my parents that we number one suspects since we live in the house..... we all had to take a polygraph test so i went to take it and they cancelled it.... now 5 months later they want us to take it........ i know that we had nothing to do with it..... i need to know what to do