MEXICO CITY (Reuters) – Mexican security forces on Tuesday arrested accused drug kingpin Damaso Lopez, believed to be locked in a bloody struggle for control of the Sinaloa Cartel against the sons of its captured leader Joaquin “El Chapo” Guzman.

The attorney general’s office announced that its agents with the help of the army had captured Lopez, 51, one of the top-ranking figures in the world’s most successful drug cartel, which has been destabilized by “El Chapo’s” extradition in January to the United States.

Guzman’s latest imprisonment triggered a violent power struggle that has led to daylight gun battles involving truck-mounted machine guns in the northwestern state of Sinaloa, with Mexican officials attributing the bloodshed to a tussle between Lopez and the former leader’s sons.

“(Lopez) is considered one of the main drug traffickers and generators of violence in Sinaloa and the south of the Baja California peninsula,” Omar Garcia, head of the Criminal Investigation Agency, told a news conference.

Last month the body of a man tossed from an airplane landed on a hospital roof in Lopez’s Sinaloan home town, Eldorado, and shootings have become common this year around the tourist resorts of Baja California.

Lopez was believed to have been seeking a new alliance with rival Jalisco New Generation Cartel, and his arrest will likely be a relief for Guzman’s family and their faction.

“This arrest reduces the possibility of an alliance that the detainee was seeking with another organized crime group that operates in several states of the country,” Garcia said.

Lopez, nicknamed “The Graduate,” was captured in an apartment in a middle-class Mexico City neighborhood in the early hours of Tuesday, a few weeks after a video emerged of him eating at a Mexico City restaurant.

He was held for several hours at the apartment with a heavy army presence outside the building before being sped in a convoy of white vehicles through the city to a unit of the attorney general’s office, live TV footage showed.

Lopez is himself a former security official, believed to have studied at Sinaloa’s state university, who Mexican officials say played a role in orchestrating Guzman’s first escape from prison in 2001, before joining the cartel.

The U.S Treasury Department in 2013 called him Guzman’s “right hand man” and froze his U.S. assets. He was indicted by a federal grand jury in the same year, accused of importing $280 million of drugs to the United States.

Guzman, who broke out twice from prison in Mexico, was recaptured for the last time in January 2016. One of the world’s most wanted drug lords, he was extradited to the United States to face charges there on Jan. 19, the eve of Donald Trump’s inauguration as U.S. president.

Trump has vowed to break the power of translational drug cartels and said that his planned wall on the U.S.-Mexico border would stem the flow of drugs into the United States. He has issued executive orders that aim to improve coordination between U.S. law enforcement agencies and their foreign partners.

(Reporting by Dave Graham and Miguel Gutierrez; Writing by Frank Jack Daniel; Editing by W Simon, Grant McCool and Lisa Shumaker)