File picture shows Mexican troops during a drug raid. The Mexican navy said the leader of the Zetas, a powerful drug cartel implicated in a grisly string of mass killings, was apparently killed in a ... more 

File picture shows Mexican troops during a drug raid. The Mexican navy said the leader of the Zetas, a powerful drug cartel implicated in a grisly string of mass killings, was apparently killed in a shootout near the US border less