Suspected Mexico Drug Chieftain Slain : Crime: He was killed in a shootout last week, a day after the possibly related assassination of a former Sinaloa official.

One of Mexico’s top mafia chiefs, Emilio Quintero Payan, was shot to death by police in a suburban shopping center on the outskirts of Mexico City, U.S. and Mexican officials confirmed Monday.

Quintero Payan, who allegedly ran heroin, cocaine and marijuana smuggling operations from his home state of Sinaloa, was killed Thursday, a day after the former attorney general of Sinaloa was gunned down in a Mexico City park.

Officials are still investigating what seem to be links between the two cases. As state attorney general until December, Rodolfo Alvarez Farber “was actively working Quintero Payan,” said a U.S. official who follows drug trafficking in Mexico. “He was very active in attacking trafficking in the state. He put a lot of pressure on Emilio and his operations.”

Two suspects, including a federal police officer, have been arrested in connection with the Alvarez Farber killing. At least one of the suspects was staying at the same hotel on the northern edge of Mexico City where Quintero Payan was staying, according to Mexico City Atty. Gen. Diego Valades.

Mexico state police said Quintero Payan was killed in a shootout after officers stopped his car for a traffic violation. But a source who asked not to be identified said the trafficker was shot twice in the head “at close range.”

Such high-profile drug killings have not been as common in Mexico as they are in Colombia. But Alvarez Farber was a highly respected combatant against drug trafficking and Quintero Payan is the second major trafficker shot to death in public in less than three weeks.

On April 12, the leader of the Ciudad Juarez drug cartel, Rafael Aguilar Guajardo, was gunned down in the Caribbean resort of Cancun, where he was vacationing with his family. A U.S. tourist also was killed in that attack.

One of the alleged gunmen detained in that case carried Morelos state police credentials and is said to have worked for competing traffickers.

Quintero Payan, 42, was the uncle of Rafael Caro Quintero, jailed for the 1985 killing of U.S. Drug Enforcement Administration agent Enrique S. Camarena. U.S. and Mexican officials considered him one of Mexico’s biggest and most dangerous traffickers.

“This is a big deal. He was one of our major traffickers,” said the U.S. official, who asked not to be identified. “He was a murderer. He killed and enjoyed killing.”

Quintero Payan reportedly was carrying federal judicial police credentials when he was killed. His associates have told officials that he enjoyed the protection of an active-duty federal police commander under Atty. Gen. Jorge Carpizo MacGregor, according to a police source.

Carpizo’s office refused any comment on the case.

The death of two major traffickers could open the way for a territorial battle among other Mexican mafia leaders. Among those who are well situated to take over the business are Juan Garcia Abrego, operating out of Tamaulipas; Amado Carrillo Fuentes, operating in the central U.S.-Mexico border area, and Joaquin (El Chapo) Guzman and Hector (El Guero) Palma in western Mexico.

Marijuana and heroin poppies are grown in Mexico, and the country is used to transship cocaine from South America to the United States. An estimated 70% of the cocaine consumed in the United States comes through Mexico.

In the last month, police have seized three cocaine shipments totaling about 15 tons. Quintero Payan is believed to have moved parts of two of those shipments.

According to Mexico state police, Quintero Payan was riding in a Chevrolet with several associates when the car was stopped by two officers in the suburban Satelite neighborhood Thursday afternoon. Police said Quintero Payan’s associates came out shooting, that he was killed and two others were wounded and taken into custody.

Two other suspects reportedly escaped.