Sincerely, if your lawyer is unable to resolve it for you, I doubt you will get your money back.
It looks like this exchange decided to throw AML policy as excuse and put your money under investigation in order to increase their capital, hoping you will not pursue a legal action against them. Basically, "hey, we are a licensed exchange and we decided to confiscate your illegal bitcoins".
As they said 'Go ahead and report us to your local law enforcement' in the support ticket, it looks like they prepared some proof (probably fake one) that your money have illegal sources and they are ready to defend themselves. In the worst scenario they will say your BTC came from SilkRoad or equal, showing that some of your transactions from a btc mixer has intersected with some darknet market. They will also defend themselves buying a team of lawyers using your money...
What I can only say is this case exposes Binance as true scammers and I am glad I didn't put a cent on their exchange. Thank you for notifying the community, I hope smart people will stop trading on that dirty player.
P.S. it looks you are not unique, some people have reported the same situation on this forum for amounts >20 BTC