Searchers make arrests , recover arms from a clan involved in massacre . Martial law follows killing of civilians last night in the province . Among the victims in the massacre were the wife and sister of political candidate Ismael `` Toto '' Mangudadatu , who had sent the women to file paperwork allowing him to run for governor of Maguindanao . Several members of powerful Ampatuan political family detained . Datu Unsay Mayor Andal Ampatuan Jr. directed killings , authorities say .
Searchers make arrests , recover arms from a clan involved in massacre . Martial law follows killing of civilians last night in the province . Several members of powerful Ampatuan political family detained . Datu Unsay Mayor Andal Ampatuan Jr. directed killings , authorities say .