In 2013, people in Michoacán and Guerrero, especially from rural areas, armed themselves against criminal cartels. Although their movements emerged from comparable contexts, their leaders and organizational forms differed in ways that affected their tactics and targets, as well as the timing of de-escalation. Whereas Guerrero’s leaders understood their struggle as defensive, Michoacán’s leaders were businessmen who saw themselves engaged in an offensive campaign. This partly explains why fatalities were greater there than in Guerrero. I further demonstrate that movement fragmentation led to lethal violence, and their organizational forms also contributed to dynamics of escalation or de-escalation in ways not fully appreciated by scholars. Specifically, the organizational form of Michoacán’s patron-sponsored autodefensas made them more vulnerable to lethal violence than were Guerrero’s community-sponsored organizations.

Practices of denunciation are at once ubiquitous and marginalised in literature on the Guatemalan armed conflict. Meanwhile, ordinary Guatemalans who spontaneously denounced neighbours, former friends and fellow villagers have largely escaped scrutiny in scholarly work on low-level perpetrators. Departing from untapped confidential documents in the Historical Archive of the National Police, this article provides the first archival study of denunciatory behaviour during the Guatemalan Civil War, specifically at the height of the conflict (1970–85). This contribution reveals both the strategic considerations that spurred state intelligence apparatuses to elicit civilian information as well as the broad range of personal, opportunistic and strategic motives that drove civilians to denounce. The case study questions scholarly consensus on the spontaneous and voluntary character of denunciation by arguing that besides providing novel pathways for opportunistic action, denunciations also opened up new strategies for survival in the face of a civil war that structured available choices.