A candidate running to be mayor in one of Mexico’s most violent cities has been killed on the first day of her campaign, adding to the death toll in what experts say could be the country’s bloodiest elections in history. Bertha Gisela Gaytán was shot in a town just outside of the city of Celaya, where she was running for Morena, Mexico’s governing party. A video on social media shows a group of activists and supporters of Morena walking through the streets before shots ring out. Adrián Guerrero, a Morena candidate for the city council, was also reportedly killed in the attack. They were the latest killings on the road to the 2 June elections, with at least 22 mayoral candidates murdered since September 2023. In part this reflects the sheer size of the elections, which will be Mexico’s biggest ever. They will decide the successor of the president, Andrés Manuel López Obrador, as well as more than 20,000 posts at the federal, state and municipal levels. Celaya is in Guanajuato, which often has more homicides than any other state in Mexico. Sixty police officers were killed in the state last year. The violence reflects the struggle for territory and business among various organised crime groups. Just hours before her death, Gaytán held a press conference in which she laid out her proposals to fight corruption and improve security in Celaya. According to Data Cívica, a research organisation that tracks political violence, roughly eight in every 10 attacks and murders happen at the municipal level. “This is where organised crime can have greater territorial control,” said Itxaro Arteta, from Data Cívica. “The municipal governments control the local budget and the police – whether those police are doing everything they should be, or letting certain things happen.” Victims are distributed among all political parties, but murders most often target the candidate challenging the incumbent. An analysis of attacks during the 2021 elections found that this was the case in 25 of 32 killings. “When a party is already governing, it is probable – though we can’t be sure of anything – that there are power agreements [between local politicians and organised crime],” said Arteta. “And when there is a change of the party, you do see an increase in violence.” Various factors complicate the protection of candidates, from the weakness of local police to the fact that only a small minority of such murders are preceded by a threat. The violence means that parties are struggling to find local candidates. Meanwhile, organised crime groups try to impose candidates on them. In the state of Michoacán, where two candidates for the same municipality were killed on the same day in February, at least 34 other candidates have decided against running. And Data Cívica’s latest research has found a negative correlation between attacks on civil servants and voter turnout. “In the end, all of this in very concrete ways undermines democracy,” said Arteta. “It leaves people with little certainty about the people they are voting for – and whether they will really be able to govern without bowing to organised crime.”