washington unite state tuesday condemn slay maltese journalist daphne caruana galizia say fbi respond malta request assistance investigate car bomb attack kill state department spokeswoman heather nauert say unite state condemn appal violence take place strong term call cowardly attack reporter dedicate fight corruption respond quickly prime minister request assistance government malta malta police force contact fbi investigation fbi provide specific assistance say nauert call thorough transparent independent probe u.s. condemn kill malta journalist say fbi assist probe