berlin germany tighten security christmas market across country year deadly truck attack berlin christmas market conservative chancellor angela merkel fire victims relatives handle case anis amri fail tunisian asylum seeker islamist link hijack truck dec. 19 kill driver plow crowd berlin christmas market kill 11 people injure dozens others 2,600 christmas market reopen late november add security staff patrol concrete barriers protect shoppers merkel week pay surprise visit site attack permanent memorial victims unveil tuesday meet monday relatives victims many say felt neglect government attack open letter merkel publish spiegel magazine month victims survivors complain chancellor meet personally kurt beck social democratic politician represent victims survivors tell reporters merkel handle tragedy stand contrast french government respond terrorist attack paris also blast call unbelievable case family one victim send bill autopsy hound bill collectors incidents must repeat beck say urge government increase hardship compensation victims relatives survivors german officials say tighten security increase information share among security force investigations expose range failures amri case experts say much work remain do cooperation intelligence agencies police authorities must improve say malte roschniski berlin security expert security tight germany mark anniversary christmas market attack