As the much-anticipated trial of Joaquín “El Chapo” Guzmán got underway in New York this week, unprecedented security measures were in place to safeguard the jurors and others involved in the case of the man accused of running the most infamous drug cartel on the planet.

“Each juror has two guards, and the security is getting tighter,” a federal law enforcement official connected to the case told Fox News on Wednesday. “And for the judge and prosecution, too.”

In another unheard of twist, before trial the 61-year-old Guzmán was made to promise he would not order the killing of any jurors - all of whom will remain anonymous. But that's a pledge that should hardly be trusted, many officials contend.

Given those security concerns, selecting a 12-person jury was, not surprisingly, no easy affair. On Tuesday, two jurors ahead to be replaced ahead of opening statements. One juror, who was kept despite bursting into tears last week, presented a medical note for dismissal. Another expressed financial hardship.

During jury selection, one member of the jury pool was rushed to hospital after suffering a panic attack. Several potential jurors expressed “extreme anxiety,” and another said she was “nervous,” and feared for her family because they lived close to the courthouse. That's where Chapo is being kept, in a newly-built basement cell to avoid traffic disruptions.

Some admitted to having googled search terms related to Chapo and killing jurors. Others said they were worried about identifying factors already having been made public. One would-be juror said co-workers had already suspected she was in the final selection group – made up of U.S. citizens from Brooklyn, Long Island, and Staten Island.

At the Brooklyn courthouse, where he sits in his solitary cell, swarms of security officers and bomb-sniffing dogs are patrolling around the clock. And those measures are expected to be in place for at least four months - the expected length of the trial.

“The Eastern Division New York Police Department (EDNY) and the U.S. Marshals Service are very experienced with high-profile trials and related jury safety and tampering issues,” said Derek Maltz, former Special Agent in Charge of the Drug Enforcement Administration Special Operations Division in New York. “But in the current world we live in, with information access and leaks, I would be concerned from the juror’s perspective, since there are so many ways to disclose the identities of the people.”

The Marshals Service, a Department of Justice agency, serves as the main agency for federal fugitive operations, the protection of officers of the federal judiciary, and the Justice Prisoner and Alien Transportation System. That all puts the Guzmán trial in their sphere of security.

Guzmán has pleaded not guilty to all 17 counts in the indictment, which accuses him of heading global operations for Mexico’s infamous Sinaloa Cartel. The U.S. had to quietly drop homicide charges from his indictment to ensure death penalty was taken off the table, making the extradition possible.

A K-9 team walks past people waiting to enter Brooklyn federal court, Tuesday, Nov. 13, 2018, in New York. Opening statements at the trial of the notorious Mexican drug lord Joaquin "El Chapo" Guzman are to begin Tuesday morning under tight security. The evidence will include the testimony of more than a dozen cooperating witnesses who prosecutors say are risking retribution by taking the stand. (AP Photo/Mark Lennihan)

The accused drug kingpin has long been known to have ordered the brutal murders of dozens – rivals, dissidents, suspected snitches, government officials or anyone who might have mildly fallen into his crosshairs. He has twice escaped from Mexico’s prisons, and effectively ran his cartel business and ordered killings from behind bars. As a result, he's currently in solitary confinement 23 hours per day.

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Robert Clark, retired FBI Assistant Special Agent in Charge of the Los Angeles bureau, said Guzmán’s destructive impact on human lives spanned into the thousands – and that’s just on the direct scale.

“If you consider the fact he was the largest supplier of cocaine and marijuana, he has negatively impacted millions of lives,” Clark said. “The violence has touched so many. However, the fear that the Sinaloa Cartel perpetrates is immeasurable.”

Clark also pointed out the jury “will be most difficult to seat the protect.” He also predicted that “within the jury, corruption will be an issue. The influence of Sinaloa and Chapo is vast and deep,” he said. “The prosecutors especially will have to be very careful - the threat is very real.”

Sinaloa is believed to have a network worldwide, including cells inside the United States.

“These people think nothing of killing anyone they don’t like, man or woman,” one U.S. official said. “They’ll decapitate, cut limbs off, shoot, drown, cut you up. It’s no big deal.”

During earlier hearings, which Guzmán often attended, law enforcement officials expressed concern over some of the “freelance journalists” in attendance. They speculated that some may have been or were working for cartel snoops, trying to ascertain early information to identify jurors, or forge relationships with those in the know.

Federal Judge Brian Mr. Cogan, 64, who has served on the United States District Court for the Eastern District of New York since 2006, is handling the case, and his known for his ruthless efficiency, calm temperament and compassion. He, too, has been given extra protection.

“Prosecutors, judges, and a whole range of personnel accept some risk to their safety, with little public recognition of the risks they are taking,” said Evan Ellis, Research Professor of Latin American Studies at tje U.S. Army War College Strategic Studies Institute.

FILE - In this Jan. 19, 2017 file photo provided U.S. law enforcement, authorities escort Joaquin "El Chapo" Guzman, center, from a plane to a waiting caravan of SUVs at Long Island MacArthur Airport, in Ronkonkoma, N.Y. Jury selection has begun under tight security at the New York trial of the Mexican drug lord. Potential jurors were quizzed Monday, Nov. 5, 2018, about their attitudes on drug trafficking and how much attention they've paid to news reports about Guzman. (U.S. law enforcement via AP, File)

While prosecutors have claimed they have unsurmountable evidence to ensure Chapo is put behind bars for life – including documents, videos and audio recordings related to the Sinaloa cartel and Guzmán’s orchestration – his defense team argues he was merely a mid-level manager for the cartel, and hardly the mythical villain he seems.

Whatever the case, security experts are confident that jurors and others at the trial will be kept safe.

“Knowing the U.S. Marshals service, they have a lot of resources dedicated to safeguarding El Chapo’s trial. Security and safety are their number one priority. They always do a great job and know exactly what is needed to protect the public and those involved with the trial,” said Joaquin Garcia, a retired FBI Special Agent and Managing Director at Pathfinder Consultants International, Inc.

Lenny DePaul, a retired Chief Inspector and Commander of the Marshals Service in New York, concurred.

“I’m well aware of the capabilities of the Marshals Service, and what they will do to keep them (the jurors) completely obscured from the public,” he said. “They will never be identified publicly, unless they come forward post-trial.”

But that is where the trouble could begin. Long after the verdict is handed down, those involved will have to watch their backs - and their mouths.

“Some of the jurors should be careful after the trial; if they think about capitalizing on big paydays for playing a role in the drug trial of the century. This is where it will become very dangerous,” Maltz said. “They should do their job, enjoy the opportunity and keep a low profile.”