Washington: In 1995, a federal grand jury in San Diego charged a little-known Mexican drug trafficker named Joaquin Guzman Loera and 22 underlings with creating a cocaine ring that stretched from Southern California to New Jersey.

Over the next two decades, as Guzman’s infamy grew and he became known simply by his nickname — El Chapo, or Shorty — the US authorities would charge him seven more times in courtrooms in New York City, Chicago, Miami and other cities where his sprawling drug network had wreaked havoc.

Prosecutors argued that his network moved hundreds of thousands of pounds of cocaine — worth billions of dollars — onto US streets.

Despite multiple requests by the United States for Mexico to extradite him, the elusive kingpin still has never set foot in a US courtroom.

But that soon might change. On Sunday night, two days after his capture in Mexico, the Mexican authorities began formal extradition proceedings to send him to the United States to face drug charges. His escape from prison last summer humiliated the Mexican authorities and raised questions about whether his incarceration there could be guaranteed.

Assuming that Guzman either does not challenge extradition or challenges it and loses, Mexico’s move sets up the prospect of one of the biggest federal trials in the United States in recent years. Guzman would join a rogue’s gallery of drug and mob figures who have stood trial in an American courtroom. Among them, Al Capone, convicted of tax evasion in Chicago in 1931; Gen. Manuel Antonio Noriega, the former dictator of Panama, convicted on drug and racketeering charges in Miami in 1992; and James Bulger, known as Whitey, convicted of murder and racketeering in Boston in 2013.

For Mexico to agree to extradite Guzman, the United States would most likely have to agree not to prosecute him on capital charges that could subject him to the death penalty. Mexico does not have a death penalty and, as a matter of policy, does not extradite defendants who could face it in another country.

With charges brought in numerous jurisdictions in the United States, another key question is where Guzman would be tried. One possibility, officials said, would be to try him in the Eastern District of New York in Brooklyn — not only because he was indicted there, but also because Attorney General Loretta E. Lynch was the US attorney in Brooklyn when the charges were brought.

And she would be the one to ultimately decide where he would be tried.

The Mexican attorney-general’s office said in a statement on Sunday night that Guzman was told that two arrest warrants from the United States were being processed. That notification formally begins extradition proceedings, and marks a sharp change in posture.

In the past, Mexican officials have been openly dismissive of the idea, and just one year ago, before Guzman’s escape, officials suggested that he would never serve time in the United States.

“El Chapo must stay here to complete his sentence, and then I will extradite him,” Jesus Murillo Karam, then the attorney-general, said in January 2015. “So about 300 or 400 years later — it will be a while.”

But US officials said the level of cooperation had improved dramatically in recent months — in no small part, they suggest, because of the fallout from Guzman’s escape.

Lynch has now met twice with Mexico’s current attorney-general, Arely Gonzalez, in discussions that she called historic. And in September, Mexico agreed to extradite several high-level fugitives, including Edgar (La Barbie) Valdez, to the United States.

“There’s a different mindset,” the Justice Department official said.

Guzman’s extradition to the United States would be “a very big deal,” said Michael Braun, who oversaw numerous Guzman investigations as the head of operations at the Drug Enforcement Administration until his retirement in 2008.

While Guzman could face US justice, Mexican authorities said they wanted to question actor Sean Penn over his October meeting with the then-fugitive.

A Mexican federal official said the attorney-general’s office also wants to speak with Mexican actress Kate del Castillo, who brokered the meeting

“That is correct, of course, it’s to determine responsibilities,” the official said on condition of anonymity, declining to provide more details, including a possible date for an interview with the stars.

White House chief of staff Denis McDonough told CNN that Penn’s meeting with Guzman “poses a lot of interesting questions for him and others involved in this so-called interview. We’ll see what happens.”

US rock magazine Rolling Stone on Saturday published the interview that Guzman gave to the actors in an undisclosed jungle clearing in Mexico.

Despite Penn’s cloak-and-dagger efforts to keep the gathering secret, another Mexican official said authorities found out about the meeting, which eventually helped them track down the Sinaloa drug cartel chief.

Guzman was recaptured on Friday in the seaside city of Los Mochis, in his native northwestern state of Sinaloa, in a military operation that left five suspects dead.