Who is killing Mexico's mayors?

The run-up to Mexico’s elections in July have been far from ordinary: many of the candidates have been killed and even more have decided that it isn’t worth the risk. But is this just part of the election process in one of the world's most violent countries or does the problem run deeper? Andrew Mueller is joined by journalist Esteban Illades, former deputy foreign minister of Mexico Andrés Rozental and the mayor of Pachuca, Yolanda Tellería Beltrán.