Ricardo Nino Villarreal, a Mexican security chief in the northeastern state of Tamaulipas, has been shot to death along with his wife, officials have confirmed. The couple were killed Saturday as they drove in neighboring Nuevo Leon state, but their bodies were found by passersby the following day. Nino Villarreal, a former military general, was one of several officials the Mexican government sent to stem a wave of violence in Tamaulipas, which has been the scene of lethal turf wars between rival drug-smuggling cartels. More than 100-high-caliber bullet casings were found at the scene of the shooting, according to reports.