In September 2013, a confidential source acting as a go-between with Mexico's most powerful drug baron, Joaquin Guzman Loera, better known as "El Chapo," delivered news I had been awaiting for years: Guzman had agreed to an on-camera, sit-down interview. I was simultaneously elated and troubled — the message came with a caveat.

In accepting our interview request, Guzman had made a request of his own: Everything that made it to air would have to be approved by him.

In a boardroom off Univision's newsroom in Miami, I met with the network's vice president of news, Daniel Coronell, a veteran investigative journalist who sharpened his reporting instincts in the darkest days of Pablo Escobar's reign in Colombia. We discussed Guzman's offer. Univision had been pursuing Guzman's story for a long time.

It was tempting to accept. Earlier that year, two producers, a cameraman and I had driven through the heart of El Chapo's kingdom in western Mexico, the isolated and lawless Sierra Madre mountain range where lush jungle is interrupted only by serpentine dirt roads and perched villages.

Outsiders here stick out and are often assumed to be with intruding rival cartels or government security forces. So we traveled with a local who drove a minivan belonging to a funeral home. As we drove, we cracked jokes to ease our nerves. The irony of driving in a vehicle accustomed to death through the backyard of Mexico's most wanted criminal was not lost on us.

For several days, we filmed in a poor and desolate part of Sinaloa, where the legendary generosity hurled around by Guzman was nowhere to be seen. We visited the area near his mother's home in the town of La Tuna, where he grew up with an abusive father who spent the proceeds from growing marijuana on booze and prostitutes, and where Guzman whetted his appetite for money selling oranges. We visited Culiacán, the state capital, and also the business hub for Guzman's international drug empire. We reported on the city's motels, owned by straw men and shadow businesses that launder Guzman's estimated $3 billion fortune, and we visited the homes of his many wives, friends and enemies. Off camera, waiters at popular restaurants proudly explained how Guzman often came down from the mountains to eat his favorite meals as other patrons were cordially ordered to hand over their cellphones.

During our reporting, we often felt as if we were being followed, our actions watched and our conversations listened to. The refrain was that nothing moved in Sinaloa without Guzman knowing about it. One day, we were filming on the road leading to the municipality of Badiraguato, near Guzman's hometown. We were recording a piece in which I said to the camera, "after growing up in a situation of extreme poverty, today this is known as El Chapo's territory." Later that night, Guzman sent us a message: "Tell the journalists that they're wrong about El Chapo's territory," explained the source close to Guzman. "It's all of Mexico." We assume a lookout on the road heard us, but we still don't know for sure.

Guzman's sphere of influence took us from Mexico to the U.S., where his cartel has burrowed hundreds of drug-running tunnels under the world's most watched border — the same one that separates him from his favorite consumer market. In Chicago, the center of Guzman's American franchise, he is as revered as in Sinaloa. Little did it matter that the city had declared Guzman Public Enemy No. 1 — a designation not seen since the days of Al Capone. Women had the face of their "hero" painted on their nails, and men tattooed their backs with artistic portrayals of Guzman's famous exploits, such as the time he first escaped prison in 2001, wearing a dress and a wig.

In Miami, we discussed Guzman's offer and quickly concluded that we could not subject our work to revisions by the subject of our reporting. We sent that message to Guzman and essentially turned down an interview with the world's most wanted and perhaps powerful fugitive.

Without the interview, our investigation ended up airing in November 2013 on Univision, the nation's largest Spanish-language network, as an hourlong TV special. It broke new ground on how Guzman had consolidated his international drug syndicate through savvy business acumen and ruthless violence from Mexico to the U.S. and as far away as Europe, Australia, China and Argentina.

And while most criminals might have hated the publicity, Guzman loved it. The source with direct contact with Guzman told me that the cartel boss had projected the Univision show on a big screen installed outdoors at one of his mountaintop camps so his bodyguards could watch it. Though dozens of Guzman's employees cheered on several occasions during the broadcast — especially the part detailing his first jailbreak in 2001 — the source says Guzman was displeased with an animation showing him in the back of an SUV, his hands and feet tied together, "like a pig being taken to the slaughterhouse." (That's how Guatemalan security forces transferred Guzman to Mexico after his arrest in 1993.)

Of course, Guzman was later recaptured, and he escaped from prison for the second time last July. A month after his escape last year, the source close to Guzman contacted us, showed us new photographs of Guzman on the run and said Guzman was once again interested in the interview. But he wanted to record the encounter on cameras he would provide.

It was around this time we learned that Guzman was in talks with Mexican actress Kate del Castillo about producing a film based on the kingpin's life. We were told a meeting between del Castillo and Guzman would occur in a matter of days.

We declined Guzman's suggestions and insisted on a Univision crew producing the interview without editorial restrictions. Over the ensuing months, we tried to nail down the interview, but increasing operations by Mexican authorities to recapture Guzman made communication almost impossible.

On Jan. 8, Guzman was captured in Sinaloa by Mexican security forces; Mexico's prosecutor claimed Guzman's contact with a film crew contributed to his arrest. A Mexican source with direct knowledge of the raid confirmed that del Castillo was part of that film crew. The next day, I called the actress. She nervously said that at the appropriate time, she would explain her involvement. "Don't call me again," she said, before hanging up.

A few hours later, Rolling Stone published an article by actor Sean Penn describing his encounter with Guzman, del Castillo and other associates. Penn later told CBS' Charlie Rose that he was able to get access to Guzman because he's not a traditional journalist and he didn't think any actual reporter would have gotten an interview. A disclosure at the top of Penn's article reads: "An understanding was brokered with the subject that this piece would be submitted for the subject's approval before publication."

The moment I heard about Penn's interview, I felt as if I had lost a long and grueling obstacle race. But still, I never regretted rejecting Guzman's conditions because I knew the capo would omit so much, especially his role in Mexico's violent drug wars.

Gerardo Reyes is the award-winning director of Univision's investigative unit. He wrote this article for the Washington Post.