Calixto Pedro Guillermo taught at a primary school and was the General Secretary of Zone 221 of Section 22 of the Mexican National Educational Workers Union. He advocated for the rights of indigenous peoples, including his own Ayuuk (Mixe) people and had been a founding partner, delegate and director of a farming cooperative, the Union of Indigenous Communities of the Northern Zone of the Isthmus. He was murdered on July 9 in San Juan Guichicovi, presumably while returning to his home in El Chocolate. His wife Marina had to identify him and recounted that on the night before the murder, she and her husband were intercepted by a man who constantly threatened them with death. According to her, this was the same man who killed Pedro Guillermo with a machete. The attacker was arrested by the municipal police.

Several organizations condemned  the teacher’s murder and organized a series of demonstrations, beginning with a march, to demand justice. In press releases and in social media, Pedro Guillermo was remembered as an honest and responsible person, who was also an active promoter of the unity and autonomy of the Ayuuk people.