Last week, Mexican authorities started investigating the murder of 72 migrants who were found slaughtered in Tamaulipas state. Complicating matters? One of the officials leading the investigation has now gone missing.
Wearing protective mask and suit, a worker walks next to a funeral home where the bodies of 72 men and women that were allegedly killed by the Zetas drug gang are held inside a refrigerated truck in San Fernando. (AP Photo/Guillermo Arias)

