you only get to deduct a business expense once. thus if you deducted supplies you can't take a theft loss. if you expensed inventory purchases you can't take a theft loss deduction. if you expense the cost of repairs you can't deduct them as damages. if you haven't otherwise deducted what was stolen, then the next questions are do you have insurance and if you do did you file an insurance claim? the IRS will disallow losses covered by insurance.
