Adrian Ramírez, known as "El Rama" or "12" was killed in a shootout with Mexican soldiers

Adrian Ramírez, known as "El Rama" or "12" was killed in a shootout with Mexican soldiers the day after two squads of gunmen massacred 15 students who were celebrating a birthday party. The killings has shocked Mexico, and called into question President Felipe Calderón's war on the violent drug cartels who are fighting for control of profitable routes to the U.S.Police interrogated José Dolores Arroyo, who is accused of being a lookout for the gunmen. Mr. Arroyo told police the gunmen, who worked for the Juárez Cartel, also known as La Linea, believed the students belonged to a rival gang known as the Artistic Assassins who work for Joaquín "El Chapo" Guzmán, Mexico's most powerful drug lord. Mr. Guzmán has been battling to take over Ciudad Juárez from the hometown Juárez Cartel for the past two years. During that period, violence has spiraled out of control. Last year, more than 2,600 people were killed in drug related violence in Ciudad Juárez, up from 1,600 in 2008.