The Ampatuans had been in control of Maguindanao since 2001. Andal Ampatuan, Sr. came first into prominence when President Corazon Aquino appointed him as officer-in-charge of Maganoy (now Shariff Aguak) in 1986 right after the People Power Revolution. Aquino, having come into power via revolutionary means, replaced every locally-elected official with officers-in-charge, although the town of Maganoy was approached differently; the ageing mayor, Pinagayaw Ampatuan, was replaced by his vice mayor, Andal Sr. He won the 1988 local elections, then served for ten years. In the 1998 elections, Andal Sr. was elected as governor.
Members of Lakas-Kampi-CMD, President Gloria Macapagal-Arroyo lists Andal Sr., as a major ally in Mindanao. Autonomous Region in Muslim Mindanao (ARMM) regional governor Zaldy Ampatuan was the party's regional chairman. Andal Sr., the family patriarch, has been provincial governor since 1998; he has been elected thrice, unopposed. Eighteen of the mayors in Maguindanao belong to the clan. The elder Ampatuan attributed his popularity to "popular support," adding "Because I am so loved by the constituencies of the municipalities, they ask me to have my sons as representatives." In the 2004 presidential elections, Arroyo won 69% of Maguindanao's vote; three years later, the party-backed coalition scored a 12-0 sweep of the senatorial elections in the province. Unable to run for a third term, he is currently grooming his son, Andal, Jr., to succeed him as governor.
With escalating tensions in the province, Arroyo, as head of the Lakas-Kampi-CMD, mediated between the Ampatuans and the Mangudadatus (both are from the same party) to prevent election-related violence. Three meetings were held in mid-2009, with one meeting hosted by then Secretary of National Defense and current party chairman Gilberto Teodoro, who is running to succeed Arroyo as president. Arroyo's adviser for political affairs Gabriel Claudio, disclosed that there was an initial agreement "in principle" that no Mangudadatu would contest Ampatuan Sr.'s gubernatorial post.
Two days before the incident, the mass grave was prepared using a backhoe emblazoned with the name of Maguindanao Gov. Andal Ampatuan Sr., and apparently owned by the Ampatuan family.
