No, it is not legal. If person A owes person B money, that does NOT give person B the right to take property of person A (outside very narrow circumstances which do not apply here--e.g. if property were made collateral or security for a debt). What your accountant has done is both a civil tort or wrong--something you can sue over--and a criminal act: she committed a form of theft, as well as tortious interference with your business. You can can sue for the return of the property (or for its value, if stolen, damaged, destroyed) and for any losses you have suffered (e.g. lost profits) due to her interference; you could also contact the police and press charges.You do have to pay her the final paycheck, though--her own wrongful act does not absolve you of your obligation to pay her.