When Mateo Martínez Ruíz disappeared on 7 July in Bello, a deindustrialised suburb just north of Medellín, I assumed his body would never be found. But on 8 August, Mateo’s badly tortured corpse was discovered in Potrerito, a rural area of Bello. According to a trusted local source, Mateo was murdered by Los Chatas, an organised crime faction, because of his political activism.