In August 2016, in Havana, Cuba, the Colombian Government signed a peace agreement with the Fuerzas Armadas Revolucionarias de Colombia-Ejército del Pueblo , FARC-EP, after four years of negotiations. The agreement provided a window of hope that Colombia's fifty-year armed struggle, the longest-running conflict in Latin America, would finally come to a close. One actor in these negotiations, whose considerable influence has been underappreciated, is the Office of the Prosecutor (OTP) of the International Criminal Court (ICC). Colombia has been under preliminary examination by the OTP since 2004. In addition to discharging its investigatory function, the ICC prosecutor has actively influenced the negotiation of two peace processes: first, the 2005 peace process with the paramilitaries; and more recently, the tumultuous negotiations with the FARC. This Comment explores the specific pathways of the OTP's influence in the Colombian peace process, and the broader lessons this episode holds for the ICC's work and for the continuing negotiations in Colombia.