do i have a case?

i was moving out of my dads house but he would not let me leave and we got into a fight, when the police arrived me and my boyfriend went to jail for assault. while I was in jail my income tax refund came to my dads address in the mail and he took all the money off the card.when I got out of jail I started calling the IRS and the card company that issued the card they sent me a replacement card but there was no money on it I was able to get the transaction history and made a copy and filed a police report then I went to the local bank where my father had used the ATM to withdraw $300 and they gave me a picture of my father using my tax refund debit card which I also made a copy of and gave to the police but I talked to the investigator a few days ago and he says that my dad admits to taking the money off my card but he is trying to say I gave him permission and I DID NOT the police are trying to say there is nothing they can do they say there is not enough evidence to charge my dad