MEXICO CITY, July 6 (Xinhua) -- The Mexican government on Friday extradited drug trafficker, Damaso Lopez, one of drug kingpin Joaquin "El Chapo" Guzman's right-hand men, to the United States, said the Attorney General (PGR).

Lopez, nicknamed "The Graduate," is the alleged leader of the Sinaloa Cartel, and has been in prison since May 2, 2017 when he was arrested in Mexico City.

Authorities said that Lopez, a former policeman, was the one-time vice director of the maximum security prison in the western state of Jalisco, from which "El Chapo" escaped in 2001. He is suspected to have been involved.

PGR official and case leader, Alberto Elias Beltran, said that Lopez was "a potential key witness" against Guzman, who is facing trial in New York in September after he was extradited from Mexico in January last year.

The extradition "signifies a watershed moment in the cooperation between both governments, particularly on the exchange of information," said Beltran.

Lopez had been wanted by the District Court for the Easter District of Virginia since 2013 to be charged on drug trafficking offenses, and conspiracy to distribute cocaine and launder profits.

Elias Beltran said that Mexican government confirmed an agreement to extradite Lopez in January.

He was facing two trials in Mexican courts for possession of methamphetamine with intent to sell and organized crime.

The PGR will ask the two judges to suspend these processes so that the situation in the United States can be defined, and so that authorities can encourage "The Graduate" to cooperate on open investigations in Mexico, said Elias Beltran.