During the summer of 2016, Santiago Aguirre divided his time between part-time university lecturing and working for an organization that helps locate missing people. Mexico was then in the news internationally because of presidential candidate Donald Trump’s promise to build a wall on the American border with its southern neighbor. However, for Aguirre, a Mexican human rights activist, the problems of the present were far more pressing than any future wall. At the time, he was in the midst of a lengthy investigation to solve the mystery of the disappearance and presumed murder of 43 students in the city of Iguala two years before. It was becoming increasingly clear that his findings were incompatible with the results of the investigation conducted by the government.