While the 58 victims were on their way to file a certificate of candidacy for Esmael Mangudadatu , vice mayor of Buluan town , they were kidnapped Kidnapping and killed Killing .

Mangudadatu was challenging Competition Datu Unsay mayor Andal Ampatuan Jr. , son of the incumbent Maguindanao governor Andal Ampatuan Sr. and member of one of Mindanao 's leading Muslim political clans , in the forthcoming Maguindanao gubernatorial election Choosing , part of the national elections Choosing in 2010 .

The people killed included Cause_to_be_included Mangudadatu 's wife , his two sisters , journalists , lawyers , aides , and motorists who were witnesses or were mistakenly identified Check as part of the convoy .