Mexican authorities say they have captured one of the Sinaloa drug cartel leaders whose struggle for control of the gang following the re-arrest of Joaquin "El Chapo" Guzman has set off a wave of violence.

Known by the nickname "El Licenciado" - the Graduate - Damaso Lopez heads a faction at odds with two sons of Guzman, the former cartel leader who was arrested last year and extradited to the United States.

The attorney general's office on Tuesday said soldiers and prosecution agents had detained a drug gang leader it called "Damaso N". A federal official confirmed the suspect is Lopez.

READ MORE: Violence in Sinaloa surges after El Chapo is extradited

Al Jazeera's John Holman, reporting from Mexico City, said the arrest was "significant because the Mexican government will be hoping that this stops the 'civil war' that's really erupted in Sinaloa" amid the power struggle between Lopez and Guzman's sons.

Authorities distributed photos showing soldiers in full battle gear guarding the entrance of an upscale apartment building on a major boulevard in Mexico City, not far from downtown.

Lopez was long considered Guzman's right-hand man and is believed to had helped him escape from a Mexican prison in 2001. 

"Believe it or not, this man was actually part of the state prosecutor's office in Sinaloa," Holman said, adding that Lopez personified "an overlap that often exists between the world of Mexico's authorities and the criminal world.

"Even more incredibly, he was a top figure in the administration system for the country's prisons, and he allegedly used that position to help Guzman escape prison over 15 years ago. Just before that happened, he resigned and seemed to dedicate himself wholly to the cartel's activities."

The US Department of the Treasury designated Lopez as a drug "kingpin" in 2013 for his role in Guzman's "narcotics trafficking activities ... and for playing a significant role in international narcotics trafficking".

As a senior Sinaloa cartel operative, Lopez is "responsible for multiple-ton shipments of narcotics from Mexico into the United States", it said.

Lopez would not be the first high-level drug suspect from outlying provinces captured in the capital. While Mexico City officials say drug cartels do not control territory in Mexico City, they acknowledge that drug lords have sometimes lived in the city and moved drug shipments through the capital.

With Guzman in jail, the Sinaloa Cartel has been controlled by Ismael "El Mayo" Zambada Garcia and Rafael Caro Quintero, two of the most traditional, old-school capos, plus Lopez, and Guzman's sons, Ivan Archivaldo Guzman Salazar and Jesus Alfredo Guzman Salazar.

Guzman faces several charges, including drug trafficking and money laundering. He has pleaded not guilty.

Source: Al Jazeera and news agencies