Ultimately, you can sue for a dissolution of the LLC, distribute the assets and go your separate ways. Meanwhile, if your partner is in jail, you can reimburse yourself for one half of the value that he has stolen from the LLC without your consent.
Your parter is still entitled to 1/2 of the business profits, but if he's in jail, then no one could stop you from closing the doors on this business, starting a new one and servicing the same customers.
He could claim breach of fidcuiary, but what of it. He won't have any money to sue you with when he gets out, anyway.
So, you have options.
Hope this helps.
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