Since 1986 the DEA and other agencies have pieced together copious information about 'El Chapo' Guzmán through intelligence sources and other methods.
Today, that is the basis for the United States’ court case against 'El Chapo' following his extradition from Mexico on January 19 this year.
The case file includes undercover recordings, intercepted communications, protected witness declarations, intercepted drug shipments and even El Chapo's own words in a 2015 video with Hollywood actor Sean Penn.
"The way to have money to buy food, to survive, is to plant opium poppies, marijuana, and ... I began to grow it," he famously told Penn.
In an interview with Jorge Ramos in Feb 2016, then U.S. Attorney General Loreta Lynch explained that El Chapo's trial will combine evidence from charges against the drug kingpin filed in several courts around the country.
"There are offices that have very strong cases against El Chapo and that is why we have to decide which is the best place, the strongest case, we must combine the cases," she said.
Some of the cases are not very well known, but they could contribute important evidence to the overall prosecution of Guzmán.
For example, a New Hampshire court has undercover recordings, according to evidence viewed by Univision Investiga.
Starting in 2009, Guzmán's organization plotted a series of shipments to Europe with a group of potential distributors. After more than a year of meetings, the Mexicans grew impatient, according to one undercover video.
"The idea is that this meeting, gentlemen, is to finalize things. I want it here, I want it this way," one of the traffickers is heard saying in the video.
Among the team sent by El Chapo was his cousin Jesús Gutiérrez Guzmán, who was in charge of communications with the drug lord.
Finally, they agreed that the merchandise would arrive by ship from Brazil to the port of Algeciras, in southern Spain. The shipment arrived, but not without setbacks.
"Four packages were missing. That happens sometimes and your people were honest and said it was their responsibility. He appreciates that. But when he orders 1,000, he expects 1,000 to arrive," one of the alleged traffickers says in another undercover recording.
Only 346 packages arrived filled with cocaine instead of the 350 agreed upon, but that was the least of the problems for the four cartel operatives. The alleged Italian mafia contacts with whom they had negotiated were in reality members of the Boston FBI. Those who received the drugs were Spanish police agents.
During the trial of Rafael Humberto Celaya Valenzuela, the only arrested person who did not plead guilty, he stated he had met El Chapo Guzmán in the mountains of Sinaloa.
All those involved in the operation were convicted. Celaya Valenzuela got 17 years in prison. Nevertheless, he continues to argue that his role was never essential in the operation and has appealed the sentence.
Despite El Chapo's carefulness, the agents got personal instructions from him about shipments, according to court documents, including an affidavit by a Boston-based FBI agent, Tucker Heap.
A convicted drug trafficker and FBI informant, referred to in documents as CHS (Confidential Human Source), even visited Guzmán in Culiacan.
It was there, in the capital of Sinaloa, that members of the Mexican Navy were able to surround Guzmán after several days of pursuit. James Dinkins directed the investigation for the office of Homeland Security.
"We were able to put together at [Homeland Security] as well as DEA some very good information that we could pass to Mexican authorities," Dinkins told Univision.
He explained that the key to the operation was the interception of communications. "When you are running one of the most diverse and global [narcotics] networks you have to be on the phone giving command and control instructions daily," Dinkins said.
The cartel doctor
Months before that operation, a DEA informant says he gave the DEA information regarding cellphones belonging to people close to El Chapo. Fearing for his safety, he spoke to Univision wearing a disguise and with an assumed name, Antonio Lopez.
"I gave this information in approximately November or December 2013. El Chapo was detained on February 22, 2014," Lopez said.
Lopez worked as a doctor in one of Mexico’s most violent cities. "They began to use me to attend to patients who could not be hospitalized," he said.
Lopez knew he was in danger if one of the injured cartel patients died in his clinic, so he only accepted the patients he knew he could save.
"Shot, tortured, burned, amputated ... everything. Not one of them died on me," he said.
Due to that success, his fame reached the highest levels of the cartel. His specialty was plastic surgery.
El Chapo became interested in the treatment of human cells to alter fingerprints and facial expressions," he told Univision.
"I think that the authorities have based their case on a lot of information from many people," he added.
After his arrest, Guzmán was held at the Altiplano prison, from where he would escape months later through a sophisticated tunnel. Once free, “El Chapo” gave an interview to Sean Penn, including the now famous video.
According to the Mexican authorities, the video provided a very important clue for his subsequent recapture.
"Guzmán Loera wanted to film a biographic movie," Mexico's Attorney General Arely Gómez announced to the media after his re-arrest in January 2016.
El Chapo went back to prison and the process of his extradition began.
At the same time, U.S. prosecutors were preparing the ground for his future trial.
In May, 2016 the Eastern District Court of New York published a new indictment against El Chapo. The court document, which focuses on Guzmán and his associate 'El Mayo' Zambada, includes drug trafficking as well as weapons possession, money laundering, and multiple murders.
"This prosecution has a very specific purpose, to try to unify all the fronts in a way that it is not only presented to the Mexican government, but also to a jury in an organized manner," explains legal expert Oscar Rodriguez.
He pointed out prior to her appointment as Attorney General, Loretta Lynch headed the Eastern District of New York where one of the main cases against El Chapo was filed.
Rodriguez suspects the strength of the government's case against Guzmán lies in the testimony of his former associates - and enemies - who are already in U.S. custody.
"They have many people in jail who negotiated directly with El Chapo," he said.
On Jan 19 El Chapo's lawyers in Mexico ran out of legal appeals and he was loaded onto a plane and flown to New York.