How a middle-class jock from a Texas border town became La Barbie, one of the most ruthless and feared cartel leaders in Mexico.

Seventeen-year-old Israel Arenas Durán disappeared after being arrested near his home in Nuevo León. He is one of more than 25,000 who have gone missing in Mexico since 2006.

How the heir to a horse racing empire became an informant on the Zetas cartel as they pushed their money laundering operations into the lucrative quarter horse trade.