guatemala city guatemalan unit telecommunications firm telefonica sa suspend customer service operations close shop weekend three employees shoot death central american nation three kill wound fourth employee occur four separate attack friday typical case extortion business areas dangerous part country company representative ask name safety concern tell reuters sunday safety employees decide suspend customer service restart tomorrow monday gradually recover normal operation representative say local media publish transcripts two suppose conversations employee movistar telefonica local unit man attempt extort 13,600 police spokesman pablo castillo say authorities investigate kill guatemala struggle endemic gang violence especially powerful mara salvatrucha also know ms-13 rival calle 18. movistar million clients guatemala telefonica suspend customer service operations guatemala kill