Mexico's military has arrested the alleged regional head of the Zetas drug cartel in connection with the recent murder of a U.S. Immigration and Customs Enforcement special agent.
Navy officials say Sergio "El Toto" Mora was detained, along with five other men, during a raid Sunday in the northern state of Coahuila.
Authorities say Mora was directly in charge of Julian Zapata Espinoza, who was arrested last week for allegedly carrying out the killing of agent Jaime Zapata.
Another agent, Victor Avila, Jr., was shot twice in the leg during the attack earlier in February in San Luis Potosi, Mexico. The men were shot when they stopped at what appeared to be a military checkpoint, possibly set up by drug traffickers. The Mexican military said it had no checkpoints in the area.
Attacks on U.S. law enforcement personnel in Mexico are rare, despite increasing U.S. contributions to Mexico's fight against drug traffickers. The last high-profile attack there was in 1985, when a Drug Enforcement Administration officer was captured, tortured and killed while on an assignment.
Mexican military forces have been engaged in a brutal struggle against violent drug cartels. At least 34,000 people have been killed in Mexico's drug war since President Felipe Calderon took office in late 2006 and began cracking down on the cartels.