MEXICO CITY (AP) — Video of a man giving a packet of cash to a brother of President Andrés Manuel López Obrador had the president — who has made the fight against corruption his signature issue — on the defensive on Friday, vowing that there would be no coverup. The image first reported by journalist Carlos Loret de Mola shows David León handing the equivalent of $7,500 to Martín Jesús López Obrador in 2015 — some three years before the president was elected.