The killing of Mr Terry was at the centre of a scandal over a failed US operation to track guns smuggled across the US-Mexican border.

BBC: Mexican arrested over US agent 'Fast and Furious' murder

Jose Antonio Elena Rodriguez, 16, was in Nogales - on the Mexican side of the border with the US state of Arizona - when he was killed in October.

BBC: Mexico boy shot in back by US patrol, post-mortem shows

At the same time, new outbreaks of dengue fever on the Mexican side of the Texas-Mexico border had US officials worried that the virus would slowly spread north.

BBC: US & Canada